Mask pattern forming method, fine pattern forming method, and film deposition apparatus

ABSTRACT

In a mask pattern forming method, a resist film is formed over a thin film, the resist film is processed into resist patterns having a predetermined pitch by photolithography, slimming of the resist patterns is performed, and an oxide film is formed on the thin film and the resist patterns after an end of the slimming step in a film deposition apparatus by supplying a source gas and an oxygen radical or an oxygen-containing gas. In the mask pattern forming method, the slimming and the oxide film forming are continuously performed in the film deposition apparatus.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of patent application Ser. No.15/714,052 filed on Sep. 25, 2017, which is a continuation of patentapplication Ser. No. 13/848,849 filed on Mar. 22, 2013, which is adivisional of patent application Ser. No. 12/567,834 filed on Sep. 28,2009. This application is based upon and claims priority to JapanesePatent Application No. 2008-251679, filed on Sep. 29, 2008, and JapanesePatent Application No. 2009-206443, filed on Sep. 7, 2009. The contentsof each of the foregoing applications are incorporated herein byreference in their entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention relates to a mask pattern forming method, a fine patternforming method and a film deposition apparatus which are used forsemiconductor processes. More particularly, the invention relates to amask pattern forming method, a fine pattern forming method and a filmdeposition apparatus which are capable of improving the precision tocorrect the pattern dimensions when forming patterns at pitches smallerthan a resolution limit of an exposure device, without increasing themanufacturing cost.

2. Description of the Related Art

With high integration of semiconductor devices, wiring patterns andisolated widths required in manufacturing processes have come to befiner in size. Generally, in order to form a fine pattern, a resistpattern is formed by a photolithographic technique, and, by using theresist pattern as a mask of etching, a thin film formed beneath theresist pattern is etched. Therefore, the photolithographic technique isimportant for this purpose. However, the microstructures of the latestsemiconductor devices have come to require a pitch of fine patternswhich is below a resolution limit of the photolithographic technique.

In the following, a pattern which is used as the mask for forming a finepattern by etching a thin film will be referred to as a mask pattern.This mask pattern may include a sacrifice film, such as an oxide film,and a resist film. Moreover, in the following, the term “fine pattern”may be used to indicate that it is inclusive of a mask pattern.

Patent Document 1 listed below discloses a technique for formingpatterns at a pitch smaller than the resolution limit. In the techniqueof Patent Document 1, a first photoresist pattern (or a first resistpattern) is formed, baking of the first resist pattern is performed, andan oxide film is formed on the first resist pattern. Then, a secondphotoresist pattern (or a second resist pattern) is formed between thefirst resist patterns, and by using the first resist patterns and thesecond resist pattern as an etching mask, a thin film formed beneath theresist patterns is etched so that a fine pattern is formed.

According to the technique of Patent Document 1, fine patterns areformed using the two photo masks, and the resolution that is higher thanthat in the case of using one photo mask can be obtained. For thisreason, the fine patterns with a pitch that is below the resolutionlimit can be formed according to the technique of Patent Document 1.

Recently, attention is focused on a technique in which a film depositionprocess to form a silicon oxide film on a pattern organic film iscombined with SWT (side wall transfer process) or LLE(lithography-lithography etching process), as a fine pattern formingmethod to form fine patterns with a pitch below the resolution limit ofthe photolithographic technique.

Patent Document 2 listed below discloses a technique for use in theabove-described fine pattern forming method to form an oxide film on aresist pattern. Although Patent Document 2 does not disclose a method offorming fine patterns with a pitch below the resolution limit, thetechnique of Patent Document 2 forms the oxide film on the resistpattern, which can prevent the thickness of the resist pattern frombeing decreased and prevent striation and wiggling from arising in theresulting fine patterns.

However, in the above-described fine pattern forming method in which thefilm deposition process to form the silicon oxide on the pattern organicfilm is combined with the fine patterns formed by SWT or LLE, thefollowing problems will arise.

Because of the resolution limit of the photolithographic techniquedescribed above, it is necessary to perform an additional dimensioncorrecting process (slimming, trimming, or smoothing) to correct thedimensions of the pattern organic film after the photolithographicprocess is performed. This will increase the manufacturing cost.

When the slimming, trimming or smoothing process is performed to correctthe dimensions of the fine patterns, a resist coater, an ashing deviceor an etching device must be used. When the film deposition process isperformed, a film deposition apparatus must be used. For this reason,the semiconductor substrate (wafer) after the slimming process isfinished is taken out from the ashing device, and it is conveyed to thefilm deposition apparatus.

However, if the wafer is taken out from the ashing device after theslimming process is finished, dust or foreign matter will adhere to thesurface of the resist pattern. If dust or foreign matter adheres to thesurface of the resist pattern, the density of defects in the siliconoxide film formed on the resist pattern will increase and the uniformityin thickness of the silicon oxide film will easily be loaded.

Moreover, when the slimming process or the film deposition process isperformed, it is difficult to maintain the dimensions of resist patternsin order to make the difference between a top width and a bottom widthof each resist pattern small. For this reason, it is difficult to formfine patterns with a good configuration.

Patent Document 1: Japanese Patent No. 2757983

Patent Document 2: Japanese Arranged-Open Patent Publication No.2004-080033

SUMMARY OF THE INVENTION

In an aspect of this disclosure, there are provided a mask patternforming method, a fine pattern forming method and a film depositionapparatus which are capable of reducing the cost of the process offorming a mask pattern (or fine pattern) from an oxide film formed on apattern organic film.

In another aspect of this disclosure, there are provided a mask patternforming method, a fine pattern forming method and a film depositionapparatus which are capable of performing the slimming process or thefilm deposition process while maintaining the dimensions of resistpatterns in order to make the difference between the top width and thebottom width of each resist pattern small, and capable of forming finepatterns with a good configuration.

In another aspect of this disclosure, there is provided a mask patternforming method including: a resist film step of forming a resist filmover a thin film; a patterning step of processing the resist film intoresist patterns having a predetermined pitch by photolithography; aslimming step of performing slimming of the resist patterns; and a filmdeposition step of forming an oxide film on the thin film and the resistpatterns after an end of the slimming step in a film depositionapparatus by supplying a source gas and an oxygen radical or anoxygen-containing gas, wherein the slimming step and the film depositionstep are continuously performed in the film deposition apparatus.

In another aspect of this disclosure, there is provided a mask patternforming method including: a step of forming a coating on a thin film; astep of forming a resist film on the coating; a first patterning step ofprocessing the resist film into first resist patterns including lineparts arrayed at a first pitch by photolithography; a first slimmingstep of performing slimming of the first resist patterns; and a filmdeposition step of forming an aluminum oxide film in ordinarytemperature on the thin film and the first resist patterns after an endof the first slimming step by supplying a source gas and anoxygen-containing gas.

In another aspect of this disclosure, there is provided a filmdeposition apparatus including: a process chamber arranged to hold avacuum pressure and to process a semiconductor substrate; a source gassupplying unit arranged to supply a source gas to the process chamber;and an oxygen radical supplying unit arranged to supply an oxygenradical or an oxygen-containing gas to the process chamber, wherein thefilm deposition apparatus is arranged so that the source gas and theoxygen radical or the oxygen-containing gas are alternately supplied tothe process chamber by the source gas supplying unit and the oxygenradical supplying unit, to form an oxide film over the semiconductorsubstrate on which resist patterns are formed, and wherein the filmdeposition apparatus is arranged to perform, before the oxide film isformed over the semiconductor substrate on which the resist patterns areformed, slimming of the resist patterns by supplying the oxygen radicalto the process chamber by the oxygen radical supplying unit.

Other aspects, features and advantages of this disclosure will beapparent from the following detailed description when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart for explaining the procedure of respective stepsof a fine pattern forming method of a first embodiment of the invention.

FIGS. 2A to 2H are cross-sectional views illustrating the configurationof the fine pattern in each of respective steps of the fine patternforming method of the first embodiment.

FIG. 3 is a vertical cross-sectional view illustrating the structure ofa film deposition apparatus used for the fine pattern forming method ofthe first embodiment.

FIG. 4 is a horizontal cross-sectional view illustrating the structureof the film deposition apparatus used for the fine pattern formingmethod of the first embodiment.

FIG. 5 is a timing chart for explaining the timing of supplying of thegases in the slimming step and the film deposition step in the finepattern forming method of the first embodiment.

FIGS. 6A, 6B and 6C are diagrams for explaining the reaction on asemiconductor substrate in the fine pattern forming method of the firstembodiment when BTBAS is used as a Si source gas.

FIGS. 7A, 7B and 7C are cross-sectional views illustrating theconfiguration of the fine pattern in the slimming step and the filmdeposition step in the fine pattern forming method of the firstembodiment.

FIGS. 8A to 8D are cross-sectional views illustrating the configurationof the fine pattern when a slimming process according to the related artand a film deposition process according to the related art areperformed.

FIGS. 9A and 9B are photographs and schematic diagrams of the resistpattern after the slimming process in the film deposition apparatus inExample 1 is performed.

FIGS. 10A and 10B are photographs and schematic diagrams of the resistpattern after the slimming process in the coater in Comparative Example1 is performed.

FIG. 11 is a diagram illustrating the width dimension of the resistpattern before and after the slimming process in the film depositionapparatus is performed.

FIG. 12 is a diagram illustrating the height dimension of the resistpattern before and after the slimming process in the film depositionapparatus is performed.

FIG. 13 is a diagram illustrating the ratio between a top width and abottom width of the resist pattern before and after the slimming processin the film deposition apparatus is performed.

FIG. 14 is a diagram illustrating the line width roughness LWR of theresist pattern before and after the slimming process in the filmdeposition apparatus is performed.

FIGS. 15A and 15B are photographs and schematic diagrams of the resistpattern after the film deposition process in Example 1 is performed.

FIGS. 16A and 16B are photographs and schematic diagrams of the resistpattern after the film deposition process in Comparative Example 1 isperformed.

FIG. 17 is a vertical cross-sectional view illustrating the structure ofa film deposition apparatus used for a fine pattern forming method of asecond embodiment of the invention.

FIG. 18 is a flowchart for explaining the procedure of respective stepsof a fine pattern forming method of a third embodiment of the invention.

FIGS. 19A to 19J are cross-sectional views illustrating theconfiguration of the fine pattern in each of the respective steps of thefine pattern forming method of the third embodiment.

FIGS. 20A to 20F are diagrams for explaining the reaction on thesemiconductor substrate in a fine pattern forming method of a fourthembodiment of the invention when DIPAS is used as a Si source gas.

FIG. 21 is a flowchart for explaining the procedure of respective stepsof a fine pattern forming method of a fifth embodiment of the invention.

FIGS. 22A to 22H are cross-sectional views illustrating theconfiguration of the fine pattern in each of the respective steps of thefine pattern forming method of the fifth embodiment.

FIG. 23 is a vertical cross-sectional view illustrating the structure ofa film deposition apparatus used for the fine pattern forming method ofthe fifth embodiment.

FIG. 24 is a horizontal cross-sectional view illustrating the structureof the film deposition apparatus used for the fine pattern formingmethod of the fifth embodiment.

FIG. 25 is a timing chart for explaining the timing of supplying of thegases in the slimming step and the film deposition step in the finepattern forming method of the fifth embodiment.

FIGS. 26A and 26B are photographs and schematic diagrams of the resistpatterns after the aluminum oxide films in Example 2 and ComparativeExample 2 are formed.

FIGS. 27A and 27B are cross-sectional views illustrating theconfiguration of the films for measuring the amounts of ashing of theresists in Examples 3 and 4 and Comparative Example 2.

FIG. 28 is a flowchart for explaining the procedure of respective stepsof a fine pattern forming method of a sixth embodiment of the invention.

FIGS. 29A to 29J are cross-sectional views illustrating theconfiguration of the fine pattern in each of the respective steps of thefine pattern forming method of the sixth embodiment.

FIG. 30 is a flowchart for explaining the procedure of respective stepsof a fine pattern forming method of a seventh embodiment of theinvention.

FIGS. 31A to 31I are cross-sectional views illustrating theconfiguration of the fine pattern in each of the respective steps of thefine pattern forming method of the seventh embodiment.

FIG. 32 is a photograph and a schematic diagram of the resist patternafter the aluminum oxide film and the silicon oxide film in Example 5are formed.

FIG. 33 is a cross-sectional view illustrating the configuration of thefilms for measuring the amounts of ashing of the resists in Examples 6and 7 and Comparative Example 3.

FIG. 34 is a diagram illustrating the dimensions of the resist patternsbefore and after the slimming processes in Example 1 and ComparativeExample 1 are performed.

FIG. 35 is a diagram illustrating the dimensions of the resist patternsafter the film deposition processes in Example 2 and Comparative Example2 are performed.

FIG. 36 is a diagram illustrating the amounts of ashing of the resistsin Examples 3 and 4 and Comparative Example 3.

FIG. 37 is a diagram illustrating the dimensions of the resist patternsafter the film deposition processes in Example 5 and Comparative Example2 are performed.

FIG. 38 is a diagram illustrating the amounts of ashing of the resistsin Examples 6 and 7 and Comparative Example 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A description will now be given of embodiments of the invention withreference to the accompanying drawings.

A fine pattern forming method and a film deposition apparatus of a firstembodiment of the invention will be described with reference to FIGS. 1to 8D. First, with reference to FIGS. 1 to 2H, the fine pattern formingmethod of the first embodiment will be described.

FIG. 1 is a flowchart for explaining the procedure of respectiveprocesses of the fine pattern forming method of this embodiment. FIGS.2A to 2H are cross-sectional views illustrating the configuration of afine pattern in each of the respective steps of the fine pattern formingmethod of this embodiment. The configuration of the fine pattern aftereach of the steps S11 to S18 of FIG. 1 is performed is equivalent to theconfiguration illustrated in each of FIGS. 2A to 2H.

As described above, a pattern which is used as the mask for forming afine pattern by etching a thin film will be referred to as a maskpattern. This mask pattern may include a sacrifice film, such as anoxide film, and a resist film. In the following, the term “fine pattern”may be used to indicate that it is inclusive of a mask pattern. Thisdefinition will be applicable also for the following embodiments whichwill be described later.

As illustrated in FIG. 1, the fine pattern forming method of thisembodiment includes a process which forms a thin film, a process whichforms a resist film, a patterning process, a slimming process, a filmdeposition process, an etching process, a process which removes a resistpattern and etches an organic film, and a process which etches the thinfilm.

The process which forms a thin film includes step S11 and the processwhich forms a resist film includes step S12. The patterning processincludes step S13 and the slimming process includes step S14. The filmdeposition process includes step S15, the etching process includes stepS16, and the process which removes a resist pattern and etches anorganic film includes step S17. The process which etches the thin filmincludes step S18.

As illustrated in FIG. 1, the processing of the step S14 and the stepS15 is performed consecutively within the same chamber (processchamber). Step S11 is a process which forms a thin film on asemiconductor substrate. FIG. 2A is a cross-sectional view illustratingthe configuration of the fine pattern after the step S11 is performed.

In step S11, as illustrated in FIG. 2A, the thin film 102 and theorganic film 103 are formed sequentially from the bottom on thesemiconductor substrate 101. By forming the pattern, the thin film 102functions as a mask when performing subsequent processes. By forming thepattern, the organic film 103 functions as a mask for forming thepattern of the thin film 102. The organic film 103 may have a functionas a coating (BARC: Bottom Anti-Reflecting Coating) at the time offorming the photoresist film 104 on the organic film 103 byphotolithography.

The semiconductor substrate 101 is not limited to a semiconductor, suchas a silicon substrate. The semiconductor substrate 101 may include astructure in which an electrically conductive film, corresponding to asemiconductor chip or an integrated circuit pattern, is formed on orwithin a semiconductor substrate, and a structure in which an interlayerinsulation film for insulating the semiconductor chip or the integratedcircuit pattern is formed on or within the semiconductor substrate.

The thin film and the organic film of this embodiment are equivalent tothe film to be etched and the coating in the claims, respectively. Thematerial of the thin film 102 is not limited, and the film whichcontains silicon nitride, silicon oxide, oxynitriding silicon, amorphoussilicon, or polysilicon can be used for the thin film 102. The thicknessof the thin film 102 is not limited, and can be in a range of 20-200 nm.

The material of the organic film 103 is not limited to a particularmaterial. Various organic base materials may be used as the organic film103, including an amorphous carbon film formed by the chemical vapordeposition (CVD) method, a polyphenol film formed by spinning, and aphotoresist, such as an i-ray resist. The thickness of the organic film103 is not limited, and can be in a range of 150-300 nm.

Step S12 is a process which forms photoresist film 104. FIG. 2B is across-sectional view illustrating the configuration of the fine patternafter the step S12 is performed. The material of the photoresist film104 is, for example, an ArF resist. The thickness of the photoresistfilm 104 is not limited, but it may be in a range of 50-200 nm.

Next, the patterning step S13 is performed. Step S13 is a process whichforms resist pattern 104 a which exposes and develops formed photoresistfilm 104 and includes the photoresist film 104. FIG. 2C is across-sectional view illustrating the configuration of the fine patternafter the step S13 is performed.

As illustrated in FIG. 2C, the resist pattern 104 a which includes thephotoresist film 104 is formed. The resist pattern 104 a functions as amask in the process which etches the organic film 103. Line width LL4and space width SS4 of the resist pattern 104 a are not limited, andthey can be equal to 60 nm. In this embodiment, each line whichconstitutes the resist pattern and has line width LL4 is defined as aline part. Therefore, the patterning process of this embodimentprocesses the resist film into the resist patterns which contain theline parts arranged at the predetermined pitch, using thephotolithography technique.

Next, the slimming process containing step S14 is performed. Step S14 isa process which performs the slimming process of the resist pattern 104a of the photoresist film 104 and forms the resist pattern 104 b of thephotoresist film 104. FIG. 2D is a cross-sectional view illustrating theconfiguration of the fine pattern after the step S14 is performed.

The slimming process is equivalent to the process which processes theconfiguration of the resist patterns in the slimming step in the claims,and is also called a trimming process.

The method of the slimming process is not limited. An example of theslimming process conditions is that the slimming process is performed inthe atmosphere containing an oxygen radical or an ozone gas and thetemperature is in a range between room temperature and 100 degrees C. Asillustrated in FIGS. 2B and 2C, the line width LL1 of the resist pattern104 b after the slimming process is smaller than the line width LL4 ofthe resist pattern 104 a before the slimming process, and therelationship between the line width LL1 and space width SS1 of theresist pattern 104 b and the line width LL4 and space width SS4 of theresist pattern 104 a is as follows: LL1<LL4 and SS1>SS4. The values ofthe LL1 and the SS1 are not limited, and the LL1 can be set to 30 nm andthe SS1 can be set to 90 nm.

In this embodiment, step S14 is performed within the process chamber ofthe film deposition apparatus for performing the film deposition processof step S15 and step S15 is performed continuously after the end of stepS14.

When performing step S14, it is necessary to select the conditions underwhich the organic film (coating) 102 is not etched. For example, theconditions of Example 1 (which will be described below) are selected andstep S14 is performed under the selected conditions, which can avoidetching of the organic film (coating) 102.

If step S14 is performed under the conditions that allows the organicfilm (coating) 102 to be etched, the organic film (coating) 102 is notetched completely and a certain part of the organic film (coating) 102may remain after the end of step S14. In such a case, the subsequentprocess to form a mask pattern cannot be performed with sufficientprecision.

Next, the film deposition process which includes step S15 is performedwithin the process chamber of the film deposition apparatus continuouslyfrom the end of step S14.

Step S15 is a film deposition process which forms the SiO2 film 105 onthe organic film 103 and the resist pattern 104 b after the end of theslimming process. FIG. 2E is a cross-sectional view illustrating theconfiguration of the fine pattern after the step S15 is performed. TheSiO2 film (silicon oxide film) is equivalent to the silicon oxide filmin the claims. Instead of the SiO2 film, a film of another material,such as a SiOx film or a film containing silicon and oxygen as principalcomponents, may be used as the film 105. An oxynitriding silicon film(SiON film) may also be used as the film 105.

The film deposition process of the SiO2 film 105 is performed in thestate where the resist pattern 104 b of the photoresist film 104remains. Because the organic film 103 generally is weak to an elevatedtemperature, it is preferred to form the SiO2 film 105 at a lowtemperature (for example, 300 degrees C. or less).

In the film deposition method of this embodiment, the film can be formedat a low temperature by using Molecular Layer Deposition (MLD) at a lowtemperature, i.e., low-temperature MLD. As a result, as illustrated inFIG. 2E, the SiO2 film 105 is formed over the entire substrate,including the location in which the resist pattern 104 b is formed andthe location in which the resist pattern 104 b is not formed, and theSiO2 film 105 is formed to cover the side faces of the resist pattern104 b. If the thickness of the SiO2 film 105 at this time is set to D,the width of the SiO2 film 105 which covers each of the side faces ofthe resist pattern 104 b is also set to D. The thickness D of the SiO2film 105 is not limited, and may be set to 30 nm.

Here, the film deposition process by the low-temperature MLD will bedescribed. In the low-temperature MLD, the process which supplies asource gas containing silicon to the process chamber and makes a siliconraw material absorb on the substrate, and the process which supplies agas containing oxygen to the process chamber and oxidizes the siliconraw material are repeated alternately.

Specifically, in the process which makes the source gas containingsilicon absorb on the substrate, an amino silane gas which has two aminogroups in one molecule, for example, bis-tertiary-butylamino silane(BTBAS), is supplied as the source gas containing silicon to the processchamber via the supplying nozzle of silicon raw material gas for apredetermined time (which is indicated by T3 in FIG. 5). Thereby, theBTBAS is made to adsorb on the substrate.

Next, in the process which supplies the gas containing oxygen to theprocess chamber and oxidizes the silicon material, an O2 gas in plasmastate, produced by the plasma generating device including the RFgenerator, is supplied as the gas containing oxygen to the processchamber via the gas supply nozzle for a predetermined time (indicated byT4 in FIG. 5). Thereby, the BTBAS absorbed on the substrate is oxidizedand the SiO2 film 105 is formed.

When the process which makes the source gas containing the siliconadsorb on the substrate and the process which supplies the gascontaining oxygen to the process chamber and oxidizes the siliconmaterial is switched, the process which performs the evacuation of theinside of the process chamber and supplies a purge gas which includesinert gas, such as N2 gas, to the process chamber in order to remove theremaining gas therein in the previous process can be performed for apredetermined time (which is indicated by T5 in FIG. 5). The purpose ofthis process is to remove the remaining gas in the process chamber.Alternatively, this process may be performed by continuing the vacuumevacuation of the process chamber and suspending the supplying of allthe gases to the process chamber, instead of supplying the purge gas tothe process chamber.

In this embodiment, the source gas containing organic silicon is used asthe Si source gas for forming the SiO2 film 105. One example of the Sisource gas containing organic silicon is amino silane base precursor. Anexample of the amino silane base precursor is a monovalent or divalentamino silane base precursor. Examples of the monovalent or divalentamino silane base precursor may include BTBAS (bis-tertiary-butylaminosilane), BDMAS (bis-dimethylamino silane), BDEAS (bis-diethylaminosilane), DPAS (dipropyl amino silane), BAS (butylamino silane), andDIPAS (diisopropyl amino silane).

Trivalent amino silane base precursor may also be used as the aminosilane base precursor. An example of the trivalent amino silane baseprecursor is TDMAS (tri-dimethyl amino silane).

Alternatively, as the Si source gas containing organic silicon, ethoxysilane base precursor may also be used instead of the amino silane baseprecursor. An example of the ethoxy silane base precursor is TEOS(tetra-ethoxy silane).

On the other hand, as the gas containing oxygen, any of NO gas, O2 gas,N2O gas, H2O gas, and O3 gas may be used, and these gases may be set inplasma state by a high frequency electric field and may be used as anoxidizing agent.

By being able to form SiO2 film below 300 degrees C., and adjusting thegas mass flow of the gas which also contains oxygen, the electric powerof an RF generator, and the pressure in a process chamber by using theplasma of the gas containing such oxygen films can be formed at 100degrees C. or less or at room temperature in the film deposition of SiO2film.

Next, an etching step including the step S16 is performed. Step S16 isan etching step which etches the SiO2 film 105 so that the SiO2 film 105remains only as side wall parts 105 a on the side walls of the resistpattern 104 b. FIG. 2F is a cross-sectional view illustrating theconfiguration of the fine pattern after the step S16 is performed.

As illustrated in FIG. 2F, the SiO2 film 105 is etched and SiO2 film 105changes into the condition of having remained only as wall part 105 awhich covers the side face of resist pattern 104 b. The etching of theSiO2 film 105 is not limited. The etching may be performed using a CFbase gas, such as CF4, C4F8, CHF3, CH3F, CH2F2, etc., a mixed gas, suchas Ar gas, or a mixed gas to which oxygen is added, if needed.

In order to etch so that only wall part 105 a of resist pattern 104 bwhich includes the SiO2 film 105 may remain, the third pattern 106 thatincludes the resist pattern 104 b and wall part 105 a is formed. Theline width of the third pattern 106 is set to LL3 and the space width isset to SS3. When the line width LL1 of the resist pattern 104 b is equalto 30 nm and the thickness D of the wall part 105 a is equal to 30 nm,LL3=LL1+D×2 can be set to 90 nm and SS3=LL1+SS1−LL3 can be set to 30 nm.

Because the surface of the SiO2 film 105 is receded in the thicknessdirection by etching, the etching performed in step S16 is also calledetching back. By performing the etching step, the oxide film is etchedand remains as side walls on the side faces of the line part of theresist pattern after the slimming process is performed. The etching stepis a process which etches the oxide film to partially remain on the sidefaces of the line part of the resist pattern after the slimming processis performed.

Step S17 includes a process which removes the resist pattern 104 b andforms the side wall part 105 a, and a process which etches the organicfilm 103 by using as a mask the side wall part 105 a formed. FIG. 2G isa cross-sectional view illustrating the configuration of the finepattern after the process which removes the resist pattern 104 b and theprocess which etches the organic film 103 are performed. By performingthe etching using a plasma of any of oxygen, nitrogen, hydrogen, andammonia, the resist pattern 104 b which includes the photoresist film104 is removed and only the side wall part 105 a remains. By etching theorganic film 103 using the wall part 105 a as a mask, as illustrated inFIG. 2G, the second pattern 107, including the side wall part 105 a andthe organic film 103, is formed in which the line width is equal to Dand the space width LL1 and the space width SS3 appear alternately.

As a result, as illustrated in FIG. 2G, the resist pattern 104 b isformed which includes the photoresist film 104 is removed, only the wallparts 105 a remain, and the second pattern 107, in which the line widthis equal to D and the space width LL1 and the space width SS3 appearalternately.

In this embodiment, the space width is set to SS2, which is equal to LL1or SS3 by making equal line width LL1 of the resist pattern 104 b andthe space width SS3 of the third pattern 106. The line width equal to Dis set anew to LL2.

As mentioned above, line width LL2 can form the second pattern 107 30 nmand for which the space width SS2 is 30 nm by LL1 being 30 nm, thethickness (width D of wall part 105 a) being 30 nm and the SiO2 film 105being SS3 30 nm. The second pattern 107 includes the wall part 105 a andorganic film (coating) 103, and is equivalent to the mask pattern in theclaims. Then, the second pattern 107 is used as a mask and the thin film102 is etched. That is, step S18 is performed.

In step S18, the thin film (film to be etched) 102 is processed usingthe second pattern (mask pattern) 107, and as illustrated in FIG. 2H,the pattern 102 a, which includes the thin film (film to be etched) 102,is formed. The organic film (coating) 103 may remain in the upper partof the pattern 102 a.

For example, etching of the thin film 102 which includes amorphoussilicon or polysilicon can be performed using plasma, such as a gas ofCl2, Cl2+HBr, Cl2+O2, CF4+O2, SF6, Cl2+N2, Cl2+HCl or HBr+Cl2+SF6. Theetching may be performed using a gas containing a CF base gas, a CHFbase gas, a CH base gas, or an oxygen gas.

The film forming method, which includes the processes from the process(step S11) which forms the organic film (coating) 103 to the process(step S17) which forms the mask pattern including the wall part 105 aand the organic film (coating) 103, is defined as the mask patternforming method in the claims.

The film forming method, which includes the mask pattern forming methodand includes the processes from the process (step S11) which forms thethin film (film to be etched) 102 to the process (step S18) which formsthe pattern 102 a including the thin film (film to be etched) 102, isdefined as the fine pattern forming method in the claims.

Next, with reference to FIGS. 3 and 4, the film deposition apparatusused for the fine pattern forming method of this embodiment will bedescribed.

FIG. 3 is a vertical cross-section view illustrating the structure ofthe film deposition apparatus used for the fine pattern forming methodof this embodiment. FIG. 4 is a horizontal cross-sectional viewillustrating the structure of the film deposition apparatus used for thefine pattern forming method of this embodiment. The heating apparatus isomitted in FIG. 4.

As illustrated in FIG. 3, the film deposition apparatus 80 of thisembodiment is arranged to perform consecutive processing of the slimmingprocess and the film deposition process in the same film depositionapparatus.

Conventionally, the slimming process is performed using an etchingdevice or an ashing device, and the film deposition process is performedusing the film deposition apparatus. For this reason, after the end ofthe slimming process, the semiconductor substrate (wafer) is pulled outfrom the ashing device, and is conveyed to the film depositionapparatus. Thus, after the end of the shrinking process, the wafer mustbe pulled out from the ashing device, and dust or foreign matter mayadhere to the surface of the resist pattern 104 b. If dust or foreignmatter adheres to the surface of the resist pattern 104 b, the defectdensity of the SiO2 film 105 formed on the resist pattern 104 b will beincreased and the uniformity of the thickness will be lowered.

On the other hand, the film deposition apparatus 80 of this embodimentis arranged to perform the slimming process using the film depositionapparatus, and to perform consecutive processing of the slimming processand the film deposition process in the same film deposition apparatus.Thus, it is possible to form the SiO2 film 105 with the defect densityreduced while keeping the surface of resist pattern 104 b pure, and itis possible to increase the uniformity of the thickness. Moreover, thecost of the conveyance and the queuing time can be reduced to increasethe productivity.

As illustrated in FIGS. 3 and 4, the film deposition apparatus 80includes a cylindrical process chamber 1 which includes a ceiling plate2 at its top portion and an opening at its bottom portion. The entireprocess chamber 1 is made of, for example, quartz, and the ceiling plate2 made of quartz is disposed at the top portion to seal the top of theprocess chamber 1.

A manifold 3 arranged in the shape of a cylindrical body made ofstainless steel is connected with the lower-end opening of the processchamber 1 via the sealing member 4 (such as an O ring). The manifold 3supports the lower-end of the process chamber 1, and a wafer boat 5 madeof quartz in which several sheets of semiconductor wafers W (forexample, 50-100 sheets) to be processed can be arranged in multiplestages may be inserted into the process chamber 1 from the lower part ofthe manifold 3. The wafer boat 5 has three pillars 6 (refer to FIG. 4),and the several wafers W are supported in the slots formed in thepillars 6.

The wafer boat 5 is arranged on the table 8 via the heat insulating mold7 made of quartz, and the table 8 is supported on the rotation shaft 10which penetrates the lid part 9 which is made of stainless steel and therotation shaft 10 opens and closes the lower-end opening of the manifold3. A magnetic fluid seal 11 is arranged for the part of the rotationshaft 10 and the rotation shaft 10 is rotatably supported with the seal11, maintaining the sealing of the rotation shaft 10 airtightly. Betweenthe periphery of the lid part 9 and the bottom end of the manifold 3,the sealing member 12 (an O ring) is interposed, maintaining the sealingnature in the process chamber 1.

The rotation shaft 10 is attached at the head of the arm 13 supported inthe lifting and lowering device (not illustrated), such as a boatelevator. The rotation shaft 10 lifts or lowers the wafer boat 5 and thelid part 9 in order to be inserted into or detached from the processchamber 1. The table 8 may be fixed to the side of the lid part 9 andthe table 8 may be arranged to process the wafer W without rotating thewafer boat 5.

The film deposition apparatus 80 is provided with the following: anoxygen-containing gas supplying device 14 which suppliesoxygen-containing gas, for example, O2 gas, into the process chamber 1;a Si source gas supplying device 15 which supplies Si source gas intothe process chamber 1; and a purge gas supplying device 16 whichsupplies inert gas, for example, N2 gas, as purge gas into the processchamber 1. The oxygen-containing gas supplying device 14 is equivalentto the oxygen radical supplying unit in the claims, and the Si sourcegas supplying device 15 is equivalent to the source gas supplying unitin the claims.

The oxygen-containing gas supplying device 14 is provided with thefollowing: an oxygen-containing gas supply source 17; anoxygen-containing gas piping 18 which draws oxygen-containing gas fromthe oxygen-containing gas supply source 17; an oxygen-containing gasdispersion nozzle 19 which includes a quartz tube which is connected tothe oxygen-containing gas piping 18, penetrates the side attachment wallof the manifold 3 to the inside, is bent upward, and extends vertically;and two or more gas discharge holes 19 a which can be separated at apredetermined spacing in the vertical portion of the oxygen-containinggas dispersion nozzle 19 and can discharge the oxygen-containing gas(the O2 gas) from each gas discharge hole 19 a horizontally towards theprocess chamber 1.

The Si source gas supplying device 15 includes a Si source gas supplysource 20, a Si source gas piping 21 which draws Si source gas from theSi source gas supply source 20, and a Si source gas dispersion nozzle 22which includes the quartz tube which is connected to the Si source gaspiping 21, penetrates the side attachment wall of the manifold 3 to theinside, is bent upward, and is prolonged vertically. In this example,two Si source gas dispersion nozzles 22 are formed (refer to FIG. 4) andeach Si source gas dispersion nozzle 22 is provided with two or more gasdischarge holes 22 a which are formed along the device direction at apredetermined spacing, in order to discharge the Si source gas whichcontains organic silicon in uniformity in the process chamber 1horizontally from each gas discharge hole 22 a. The number of Si sourcegas dispersion nozzles 22 may be one. The purge gas supplying device 16includes a purge gas supply source 23, a purge gas piping 24 which drawspurge gas from the purge gas supply source 23, and a purge gas nozzle 25which is connected to the purge gas piping 24 and provided bypenetrating the side attachment wall of the manifold 3. As the purgegas, inert gas, for example, N2 gas, can be used conveniently.

The oxygen-containing gas piping 18, the Si source gas piping 21, andthe purge gas piping 24 are provided with the valves 18 a, 21 a and 24 aand the flow control devices 18 b, 21 b and 24 b, respectively, in orderto supply the oxygen-containing gas, the Si source gas, and the purgegas, respectively.

The plasma generating device 30 which forms the plasma ofoxygen-containing gas is formed in some side attachment walls of theprocess chamber 1. The plasma generating device 30 includes a verticallyextending opening 31 by removing the side attachment wall of the processchamber 1 by a predetermined width along the sliding direction, and aplasma partitioning wall 32 which is airtightly welded to the outer wallof process chamber 1. The plasma partitioning wall 32 is formed toextend vertically and made of quartz.

The plasma generating device 30 is provided with the following: a pairof plasma electrodes 33 arranged facing mutually the outside surfaces ofthe side walls of the plasma partitioning wall 32 along the slidingdirection; and an RF generator 35 which is connected to the plasmaelectrode 33 via the supplying line 34 and supplies high-frequency powerso that the plasma of oxygen-containing gas may occur by applying thehigh-frequency voltage of 13.56 MHz to the plasma electrodes 33 from theRF generator 35. The frequency of the high-frequency voltage is notlimited to 13.56 MHz, and other frequencies, for example, 400 kHz, maybe used for it.

By forming the plasma partitioning walls 32, some side attachment wallsof the process chamber 1 will be depressed outward and will be in thecondition that the interior space of the plasma partitioning wall 32 isopen to communicate with the interior space of the process chamber 1.The opening 31 is formed in the sliding direction so that all the wafersW currently held in the wafer boat 5 can be covered in the heightdirection.

The oxygen-containing gas dispersion nozzle 19 extends upward in theinside of the process chamber 1 and bent to the outside of the radialdirection of the process chamber 1, and it is directed towards the upperpart along with the back portion (which is most distant from the centerof the process chamber 1) within the plasma partitioning wall 32.

For this reason, when the RF generator 35 is turned on and a highfrequency electric field is formed between both electrodes 33, theoxygen gas is discharged from the gas discharge hole 19 a of theoxygen-containing gas dispersion nozzle 19, turned into a plasma stateand spreads towards the center of the process chamber 1.

An insulation protection covering 36 made of quartz is attached to theoutside of the plasma partitioning wall 32 to cover the plasmapartitioning wall 32. The plasma electrode 33 can be cooled by supplyingthe nitrogen gas which is cooled through the refrigerant passage (notillustrated) which is arranged in the inner part of the insulationprotection covering 36.

The two Si source gas dispersion nozzles 22 are provided in the locationto interpose the inside wall opening 31 of the process chamber 1. Theamino silane gas as the Si source gas can be supplied to the centraldirection of the process chamber 1 from the gas discharge holes 22 aformed in the Si source gas dispersion nozzle 22.

On the other hand, the exhaust port 37 for carrying out the evacuationof the inside of the process chamber 1 is arranged in the portion of theopposite side of the opening 31 of the process chamber 1. The exhaustport 37 is formed by removing the side attachment wall of the processchamber 1 to the sliding direction. The exhaust-port cover member 38which is provided for covering the exhaust port 37 is attached to theportion corresponding to the exhaust port 37 of the process chamber 1 bywelding. The exhaust-port cover member 38 extends upward in accordancewith the side attachment wall of the process chamber 1, and includes thegas outlet 39 located above the process chamber 1. Decreasing of theinternal pressure of the process chamber to a vacuum pressure isperformed by using the evacuation device containing the vacuum pump (notillustrated) from the gas outlet 39. A heating apparatus 40 is arrangedin the form of a housing which surrounds the periphery of the processchamber 1 and heats the process chamber 1 and the wafer W in the core.

The control of each component part of the film deposition apparatus 80,for example, supplying and stopping of each gas by opening and closingof the valves 18 a, 21 a, and 24 a, the control of the gas mass flow bythe mass-flow controllers 18 b, 21 b, and 24 b, the on-off control ofthe RF generator 35, the control of the heating apparatus 40, etc. areperformed by the controller 50 which includes a microprocessor(computer).

A user interface 51 which includes a keyboard which performs inputoperation of a command etc. in order to allow a process managing personto manage the film deposition apparatus 80, a display which displays theoperating condition of the film deposition apparatus 80, etc. isconnected to the controller 50.

A memory part 52 which stores the control program for performing variousprocesses with the film deposition apparatus 80 by control of thecontroller 50 and the program (recipe) for causing each part of the filmdeposition apparatus 80 to perform the process according to theprocessing conditions is connected to the controller 50. The recipe maybe stored in a storage medium in the memory part 52. Examples of thestorage medium may include a hard disk, a semiconductor memory, aCD-ROM, a DVD, and a flash memory. Alternatively, the recipe may bedownloaded suitably through a leased circuit line from an externaldevice.

The desired process is performed with the film deposition apparatus 80under control of the controller 50 by calling an arbitrary recipe fromthe memory part 52 in accordance with the command from the userinterface 51 and performing the same by the controller 50 if needed.

Next, with reference to FIGS. 5-6C, the slimming process and filmdeposition process of the fine pattern forming method of this embodimentwill be described.

FIG. 5 is a timing chart for explaining the timing of supplying of thegases in the slimming process and the film deposition process in thefine pattern forming method of this embodiment. FIGS. 6A-6C are diagramsfor explaining the reaction on the semiconductor substrate in the finepattern forming method of this embodiment when BTBAS is used as the Sisource gas.

For example, the semiconductor wafer W is loaded by raising the waferboat 5 from the lower part of the process chamber 1 which is heldbeforehand at a predetermined temperature, and the inside of the processchamber 1 is turned into the sealing space by closing the lower-endopening of the manifold 3 by the lid part 9. The semiconductor wafer Wwith the diameter of 300 mm is illustrated. While maintaining the insideof the process chamber 1 to the predetermined vacuum pressure for thewafer processing, the supply power of the heating apparatus 40 iscontrolled, the wafer temperature is raised, the process temperature isheld, and the wafer boat 5 is rotated.

However, in this embodiment, before starting the film depositionprocess, the slimming process for processing the configuration of theresist pattern is performed.

As illustrated in FIG. 5, in the slimming process, step S1 (slimmingprocess), which supplies the oxygen radical derived from theoxygen-containing gas to the process chamber 1, and processes theconfiguration of the resist pattern, is performed. In the process whichsupplies the oxygen radical of step S1, the O2 gas, as theoxygen-containing gas from the oxygen-containing gas supply source 17 ofthe oxygen-containing gas supplying device 14, is discharged from thegas discharge hole 19 a via the oxygen-containing gas piping 18 and theoxygen-containing gas dispersion nozzle 19. At this time, the RFgenerator 35 of the plasma generating device 30 is turned ON, a highfrequency electric field is formed, and the oxygen-containing gas (theO2 gas) is turned into a plasma state by the high frequency electricfield. Furthermore, the oxygen-containing gas in the plasma state issupplied into the process chamber 1. Thereby, the photoresist whichforms the resist pattern is processed by the asking, and the width andthe height of the resist pattern are decreased, namely, the slimmingprocess is performed. The time T1 of this process in a range of 1 to 600sec is illustrated.

Although the flow rate of the oxygen-containing gas varies depending onthe number of sheets of semiconductor wafers W loaded, the flow rate ina range of 100-20000 mL/min (sccm) is illustrated. The frequency of theRF generator 35 which is equal to 13.56 MHz is illustrated, and thepower of the RF generator 35 in a range of 5-1000 W may be used. Theinternal pressure of the process chamber 1 in a range of 13.3-665 Pa isillustrated.

In this case, examples of the oxygen-containing gas may include O2 gas,NO gas, N2O gas, H2O gas, and O3 gas, and the plasma-state gas by thehigh frequency electric field is used. The oxygen radical is notrestricted to the plasma of the oxygen-containing gas, but it ispreferred that the O2 plasma is used as the plasma of theoxygen-containing gas. By using the oxygen radical or the plasma of theoxygen-containing gas as the oxidizing agent, the substrate temperatureat the time of performing the slimming process may be 300 degrees C. orless, or may be 100 degrees C. or less, and a room temperature may beused for the slimming process.

Next, the film deposition process is performed within the processchamber 1 continuously from the end of the slimming process. First,after the end of the slimming process, step S2 is performed beforestarting the film deposition process. Step S2 is a process which removesthe gas remaining in the process chamber 1 and produces a desiredreaction in the following process after step S1. It is performed bysupplying inert gas, for example, N2 gas, as the purge gas via the purgegas piping 24 and the purge gas nozzle 25 from the purge gas supplysource 23 of the purge gas supplying device 16, in order to perform theevacuation of the inside of the process chamber 1. The time T2 of thisstep S2 in a range of 1 to 60 sec is illustrated. The purge gas flowrate in a range of 0.1-5000 mL/min (sccm) is illustrated.

As long as this step S2 can remove the gas which remains in the processchamber 1, the supplying of all the gas may be suspended withoutsupplying the purge gas. However, the remaining gas in the processchamber 1 is removable by supplying the purge gas for a short time. Thepressure in the process chamber 1 in a range of 0.133-665 Pa isillustrated. The substrate temperature, which is in a range of roomtemperature (25 degrees C.) to 700 degrees C., or desirably in a rangeof room temperature (25 degrees C.) to 500 degrees C., or more desirablyin a range of room temperature (25 degrees C.) to 300 degrees C., isillustrated.

While maintaining the inside of the process chamber 1 to thepredetermined vacuum pressure continuously, the supply power to theheating apparatus 40 is controlled, the wafer temperature is raised, theprocess temperature is held, the wafer boat 5 is rotated, and the filmdeposition process is started.

As thus illustrated in FIG. 5, in this embodiment, the step S3, whichsupplies the Si source gas containing organic silicon to the processchamber 1 and the Si source is adsorbed, and the step S4 which suppliesthe oxygen radical to the process chamber 1 and the Si source gas isoxidized, are repeated alternately. In this embodiment, step S5 whichremoves the gas remaining in the process chamber 1 from the inside ofthe process chamber 1 is performed between step S3 and step S4.

In step S3 in this embodiment, the amino silane gas (BTBAS) as the Sisource gas from the Si source gas supply source 20 of the Si source gassupplying device 15 is supplied from the gas discharge hole 22 a via theSi source gas piping 21 and the Si source gas dispersion nozzle 22 tothe inside of the process chamber 1 for the supplying time T3. Thereby,the Si source gas is adsorbed by the semiconductor wafer. The time T3 ina range of 1 to 600 sec is illustrated. The flow rate of the Si sourcegas in a range of 10-500 mL/min (sccm) is illustrated. The pressure inthe process chamber 1 in a range of 13.3-665 Pa is illustrated.

Similar to the step S1, in the process which supplies the oxygen radicalof step S4, the O2 gas is discharged from the gas discharge hole 19 avia the oxygen-containing gas piping 18 and the oxygen-containing gasdispersion nozzle 19 as the oxygen-containing gas from theoxygen-containing gas supply source 17 of the oxygen-containing gassupplying device 14. At this time, the RF generator 35 of the plasmagenerating device 30 is turned ON, a high frequency electric field isformed, and the oxygen-containing gas (the O2 gas) is turned into aplasma state by the high frequency electric field. The oxygen-containinggas in the plasma state is supplied to the process chamber 1. Thereby,the Si source adsorbed by the semiconductor wafer W is oxidized to formSiO2. The time T4 of this process in a range of 1 to 600 sec isillustrated. Although the flow rate of the oxygen-containing gas variesdepending on the number of the sheets of semiconductor wafers W loaded,the flow rate in a range of 100-20000 mL/min (sccm) is illustrated. Thefrequency of the RF generator 35 which is equal to 13.56 MHz isillustrated and the power of the RF generator 35 in a range of 5-1000 Wis used. The pressure in the process chamber 1 in a range of 13.3-665 Pais illustrated.

Also in this case, examples of the oxygen-containing gas may include O2gas, NO gas, N2O gas, H2O gas, and O3 gas, and the gas in plasma stategenerated by the high frequency electric field is used as the oxidizingagent. The oxygen radical as the oxidizing agent is not restricted tothe plasma of the oxygen-containing gas, but it is preferred to use theplasma of the oxygen-containing gas, particularly the O2 plasma.Moreover, the temperature at which the SiO2 film is formed in the filmdeposition step may be 300 degrees C. or less. It is preferred that, bysupplying the oxygen radical (especially the plasma of theoxygen-containing gas) as the oxidizing agent, the temperature is belowa heat-resisting temperature of the resist film (or 100 degrees C. orless), or the temperature may be set to room temperature.

Step S5 performed between step S3 and step S4 is a process which removesthe gas which remains in the process chamber 1, and produces a desiredreaction in the following process after step S3 or step S4. Step S5 isperformed by supplying an inert gas, for example, N2 gas, as a purge gasvia the purge gas piping 24 and the purge gas nozzle 25 from the purgegas supply source 23 of the purge gas supplying device 16, carrying outthe evacuation of the inside of the process chamber 1. The time T5 ofthe step S5 in a range of 1 to 60 sec is illustrated. The purge gas flowrate in a range of 0.1-5000 mL/min (sccm) is illustrated.

As long as the step S5 can remove the gas which remains in the processchamber 1, the supplying of all the gas may be suspended withoutsupplying the purge gas. However, the remaining gas in the processchamber 1 is removable by supplying the purge gas for a short time. Thepressure in the process chamber 1 in a range of 0.133-665 Pa isillustrated. Thus, by repeating and supplying the Si source gas and theoxygen-inclusion plasma as the oxygen radical alternately, the step S5which removes the gas from the inside of the process chamber 1 isperformed between step S3 and step S4. The thin films of SiO2 can belaminated to reach the predetermined thickness.

The example of the reaction at this time is illustrated in FIGS. 6A to6C. In this example, BTBAS is used as the Si source gas.

As illustrated in FIG. 6A, an OH group exists in the surface of SiO2already deposited film, and BTBAS is supplied to the surface of thealready deposited film as a Si source. Moreover, the Si of BTBAS reactswith the O of the surface OH group, and makes the O secede from thetrimethyl amino acid in the process (step S3) adsorbed in the Si source,as illustrated in FIG. 6B.

Since BTBAS, which is the amino silane which has two amino acids, has ahigh reactivity with OH, the adsorption reaction of Si advancespromptly. The trimethyl amino group disconnected at this time is removedfrom the process chamber 1 in step S3.

In the following oxidation process (step S4), as illustrated in FIG. 6C,the Si compound, after the trimetyl amino group breaks away, is oxidizedby the oxygen radical like the O2 gas plasma, and SiO2 is formed(however, H bonds to the surface and the OH group is formed). Thus, ahigh temperature of the oxidation reaction using the oxygen radical likethe O2 gas plasma is not needed, unlike a pure chemical reaction, andthe reaction at a low temperature is possible.

BTBAS is the amino silane gas which has two amino groups in one moleculeused as the Si source gas. Examples of the amino silane gas may includeBTBAS, BDBAS (bis-diethyl amino silane) and BDMAS (bis-dimethylaminosilane). It is also possible to use for the Si source gas an aminosilane gas which has three or more amino groups in one molecule, and itis also possible to use an amino silane gas which has one amino group inone molecule.

By performing the film deposition process in this embodiment in whichthe source gas which contains the organic silicon is used as the Sisource, the film can be formed at a low temperature which is 100 degreesC. or less. If the temperature is increased above 100 degrees C., thethickness dispersion may become large and the thermal influence on theresist pattern 104 b may be taken into consideration, and it ispreferred that the temperature is 100 degrees C. or less.

Next, the slimming process in the fine pattern forming method of thisembodiment will be described with reference to FIGS. 7A-8D. FIGS. 7A-7Care cross-sectional views illustrating the configuration of the finepattern in the slimming process and the film deposition process in thefine pattern forming method of this embodiment. FIGS. 8A-8D arecross-sectional views illustrating the configuration of the fine patternin the slimming process and the film deposition process according to therelated art. FIG. 7A, FIG. 7B and FIG. 7C correspond to FIG. 2C, FIG. 2Dand FIG. 2E, respectively, and FIG. 8A, FIG. 8B and FIG. 8D correspondto FIG. 2C, FIG. 2D and FIG. 2E, respectively.

In the fine pattern forming method of this embodiment, after thepatterning process illustrated in FIG. 2C is performed, thesemiconductor wafer W by which resist 104 is processed into resistpattern 104 a is introduced in film deposition apparatus 80, asillustrated in FIG. 7A.

Next, as illustrated in FIG. 7B, the slimming process (slimming processin the film deposition apparatus) of processing the configuration of theresist pattern 104 a into the resist pattern 104 b using theoxygen-containing gas plasma or the ozone gas within the film depositionapparatus 80 is performed.

Next, as illustrated in FIG. 7C, the film deposition process which formsthe SiO2 film 105 on the organic film 103 and the resist pattern 104 bafter the end of the slimming process, by using the amino silane baseprecursor and the oxygen-containing gas plasma or the ozone gas, isperformed within the film deposition apparatus 80.

Then, the semiconductor wafer W is introduced into the etching device,and the etching step illustrated in FIG. 2F is performed.

According to the related art, as illustrated in FIGS. 8A-8D, after thepatterning process illustrated in FIG. 2C is performed, thesemiconductor wafer W by which resist 104 is processed into resistpattern 104 a is introduced into resist coater (or asking device) 81 asillustrated in FIG. 8A.

Next, as illustrated in FIG. 8B, the slimming process of processing theconfiguration of resist pattern 104 a into resist pattern 104 b by usingthe photolithographic technique (or oxygen-containing gas plasma) withinthe resist coater (or the ashing device) 81 is performed. Thesemiconductor wafer Win which the resist 104 is processed into theresist pattern 104 b is introduced into the film deposition apparatus80, as illustrated in FIG. 8C.

Next, as illustrated in FIG. 8D, the film deposition process isperformed, which uses an amino silane base precursor, theoxygen-containing gas plasma, or the ozone gas, and forms SiO2 film 105within the film deposition apparatus 80 on resist pattern 104 b, intowhich the configuration is processed according to the slimming process,and organic film 103. Then, semiconductor wafer W is introduced into anetching device, and the etching step illustrated in FIG. 2F isperformed.

When performing the slimming process (slimming process in the coater)within a resist coater, the solution is applied which develops negativesat an elevated temperature within a developing device(high-temperature-development process), and contains an acid in a resistpattern within the coater (oxidation process). The slimming of theresist pattern may be performed by heat-treating, diffusing an acid,forming a new soluble layer on the surface of a resist pattern into aresist pattern (acid diffusion process), or developing the soluble layerwithin the developing device (development).

When the steps of FIGS. 7A to 7C and the steps of FIGS. 8A to 8D arecompared, there are more processes than the fine pattern forming methodof this embodiment illustrated in FIGS. 7A-7C in the method of formingthe fine pattern according to the related art illustrated in FIGS.8A-8D. Conventionally, the slimming process is performed with the resistcoater (or ashing device). In contrast, in the fine pattern formingmethod of this embodiment, the slimming process and the film depositionprocess can be continuously performed within the same process chamber ofthe film deposition apparatus. Thus, the cost of the process forperforming the slimming process can be reduced.

Although the example which performs the slimming process with the resistcoater (or ashing device) is explained as the conventional fine patternforming method in the Comparative Example, there is also an examplewhich performs the slimming process (trimming process) with an etchingdevice instead of the resist coater (or ashing device). Since the finepattern forming method of this embodiment can process the slimmingprocess and the film deposition process continuously, the cost of theprocess can be reduced.

In the mask pattern forming method of this embodiment, the substrate 101in which the resist pattern 104 a of the resist film 104 was formed instep S13 is introduced into the film deposition apparatus which is usedto form the silicon oxide film 105 in step S15 (film depositionprocess).

Next, the slimming process is performed which carries out trimming ofthe configuration of the resist pattern 104 a using theoxygen-containing gas plasma or the ozone gas within the film depositionapparatus, to form the resist pattern 104 b.

Next, the surface of the resist pattern 104 b after the slimming processis performed is then covered isotropically by the silicon oxide film 105within the film deposition apparatus.

As described above with reference to FIGS. 2B-2D, in step S14, the widthdimension LL4 of the resist pattern 104 a of the resist film 104 isdecreased to the width dimension LL1 of the resist pattern 104 b. Instep S15, the width dimension LL1 of resist pattern 104 b increases toLL1+D×2, when silicon oxide film 105 which has a thickness D covers bothsides of each train of resist pattern 104 b. It is possible to finelyadjust the slimming time (indicated by T1 in FIG. 5) in step S14 and thefilm deposition time (T6=T3+T5+T4+T5+T3+ . . . as illustrated in FIG. 5)in step S15, respectively. What is necessary is just to adjust the filmdeposition time (number of times which repeats and supplies the siliconsource gas and the oxygen-containing gas in the case of MLD) of thesilicon oxide film in step S15, according to the amount of slimming instep S14.

Therefore, since the ratio of the slimming time T1 and the filmdeposition time T6 can be finely tuned independently, in the secondpattern (mask pattern) 107 in step S17, the space widths LL3 and SS3 canbe made equal. As a result, the second pattern (mask pattern) 107 can beused as the pattern of dense equidistant placement which has a pitch ofthe abbreviated half of the resist pattern 104 b.

Concretely, by setting the slimming time T1 to 10 min, the LL1 can beset to 10 nm. If the T3, T4 and T5 in FIG. 5 are set to 15 sec, 30 secand 15 sec, respectively, and the number of times of repetition is setto 50 times, the film deposition time T6 can be set to 50 min, and the Dcan be set to 10 nm. Thereby, the second pattern (mask pattern) 107 canbe used as the pattern of dense equidistant placement.

Next, the slimming process can be performed holding in this embodiment,with reference to FIGS. 9A to 16B, in order to reduce the differencebetween the top width and the bottom width of the resist pattern, and aneffect will be described which can precisely control the configurationof the resist pattern by which slimming process is performed will bedescribed. By measuring the width dimension of the resist pattern afterthe end of the slimming process, the evaluation result.

As Example 1, the slimming process (slimming process in the filmdeposition apparatus) is performed on the resist pattern afterperforming a patterning process using the oxygen-containing gas plasmain the film deposition apparatus, and the film deposition process ofsilicon oxide is performed after that. The conditions of the slimmingprocess (slimming process in the film deposition apparatus) and the filmdeposition process in Example 1 are illustrated below.

Example 1

(A) Slimming Process in Film Deposition Apparatus

-   Oxygen-containing gas: O2 gas-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 66.7-227 Pa-   Gas mass flow: 5-30 slm-   RF generator frequency: 13.56 MHz-   RF generator power: 50-500 W    (B) Film Deposition Process    (1) Source Gas Supplying Conditions-   Source gas: DIPAS (LTO520)-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 26.7-667 Pa-   Gas mass flow: 50-1000 sccm-   Supplying time: 1-10 sec    (2) Oxidizing Gas Supplying Conditions-   Oxidizing gas: oxygen gas-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 66.7-227 Pa-   Gas mass flow: 5-30 slm-   Supplying time: 5-30 sec-   RF generator frequency: 13.56 MHz-   RF generator power: 50-500 W    (3) Repetition Conditions-   Total cycle: 140-150 cycles

FIGS. 9A and 9B illustrate SEM photographs (left-hand side) of the crosssection of the resist pattern from the slanting upper part and the frontpart, respectively, and the corresponding schematic diagrams (right-handside) of the resist pattern.

As illustrated in FIGS. 9A and 9B, CD denotes a width dimension of theresist pattern (which is equal to D indicated in FIG. 2E), and H denotesa height dimension of the resist pattern. T denotes a top widthdimension at the top of the resist pattern, M denotes a width dimensionof the resist pattern at half of the height from the bottom to the topthereof, and B denotes a bottom width dimension at the bottom of theresist pattern.

As Comparative Example 1, a high-temperature-development process isperformed on the resist pattern after the patterning process isperformed, the resist pattern is oxidized, and the acid diffusionprocess is performed, the development process is performed, the slimmingprocess (the slimming process in the coater) is performed, and the filmdeposition process is performed so that the silicon oxide is formed.

The conditions of the slimming process (slimming process in the coater)and the film deposition process in Comparative Example 1 are illustratedbelow.

Comparative Example 1

(A) Slimming Process in Coater

(1) High-Temperature-Development Processing Condition Developer: NMD3

-   Process temperature: 23-50 degrees C.-   Processing time: 60 sec    (2) Oxidation Process Conditions-   Applied fluid: TK thinner-   Rotating speed: 1000-1500 rpm-   Processing time: 60 sec    (3) Acid Diffusion Process Conditions-   Process temperature: 50-90 degrees C.    (4) Development Conditions-   Developer: NMD3-   Process temperature: 23-50 degrees C.-   Processing time: 60 sec    (B) Film Deposition Process-   Same as those of film deposition process of Example 1

FIGS. 10A and 10B illustrate the photographs (left-hand side) of thecross section of the resist pattern from the slanting upper part and thefront part, respectively, and the corresponding schematic diagrams(right-hand side) of the resist pattern.

The definitions of CD, H, T, M, and B which indicate the respectivedimensions of the resist pattern as illustrated in FIGS. 10A and 10B arethe same as those of the definitions in Example 1 as illustrated inFIGS. 9A and 9B. The magnification in FIGS. 10A and 10B is the same asthe magnification in FIGS. 9A and 9B.

As illustrated, the size of the resist pattern in FIGS. 9A and 9B islarger than that in FIGS. 10A and 10B, and the difference between thetop width and the bottom width of the resist pattern in FIGS. 9A and 9Bis smaller than that in FIGS. 10A and 10B.

Next, FIG. 34 illustrates the dimensions CD, H, T, M, B, and the ratioT/B of the top width and the bottom width of each of the resist patternsobtained in Example 1 and Comparative Example 1. FIG. 34 illustrateseach width dimension of the resist pattern before the slimming process.

As compared with each dimension before performing the slimming processin the film deposition apparatus for each dimension of the resistpattern after performing slimming process in a film deposition apparatusbased on each width dimension illustrated in FIG. 34, or each dimensionafter performing the slimming process in the coater, it is illustratedin the graphs of FIG. 11 to FIG. 14.

FIG. 11 illustrates the width dimension CD of the resist pattern, FIG.12 illustrates the height dimension H of the resist pattern, FIG. 13illustrates the ratio T/B of the top width and the bottom width of theresist pattern, and FIG. 14 illustrates the line width roughness (LWR)of the resist pattern. Here, the line width roughness (LWR) is aparameter which expresses a dispersion of the CD values at two or moreportions in the pattern extending direction (the direction of Y) inFIGS. 9A to 10B, which is equivalent to 3×σ when setting the standarddeviation to σ.

As illustrated in FIG. 11, the width dimension CD of the resist patternby the slimming process in the film deposition apparatus decreases fromthe level before the process is performed, regardless of the value towhich the power of the RF generator is adjusted. In contrast, the widthdimension CD of the resist pattern by the slimming process in the coaterdoes not decrease.

As illustrated in FIG. 12, the height dimension H of the resist patternby the slimming process in the film deposition apparatus decreases fromthe level before the process is performed, regardless of the value towhich the power of the RF generator is adjusted. In contrast, the heightdimension H of the resist pattern by the slimming process in the coaterdoes not decrease.

As illustrated in FIG. 13, the ratio T/B of the top width and the bottomwidth of the resist pattern by the slimming process in the filmdeposition apparatus increases from the level before the process isperformed or the level of the slimming process in the coater andapproaches the value 1, regardless of the value to which the power of anRF generator is adjusted. Namely, the difference between the top widthand the bottom width of the resist pattern can be reduced by theslimming process in the film deposition apparatus from the level of theslimming process in the coater.

As illustrated in FIG. 14, the LWR of the resist pattern by the slimmingprocess in the film deposition apparatus is smaller than the levelbefore the process is performed, regardless of the value to which thepower of the RF generator is adjusted. Although it is a value comparableas the value by the slimming process in the coater, the amount ofdecline of the CD value by the slimming process in the coater is largerthan the amount of decline of the CD value by the slimming process inthe film deposition apparatus. The ratio of the LWR to the amount ofdecline of the CD value by the slimming process in the film depositionapparatus is smaller. Thus, the value of the LWR which expresses thedispersion of the CD values in the pattern extending direction (thedirection of Y) by the slimming process in the film deposition apparatusis improved when compared to the slimming process in the coater.

FIGS. 15A and 15B illustrate the SEM photographs of the resist patternafter (B) the film deposition process is performed in Example 1. FIGS.15A and 15B are the photographs (left-hand side) of the cross section ofthe resist pattern from the slanting upper part and the front part,respectively, and the corresponding schematic diagrams (right-hand side)of the resist pattern. FIGS. 16A and 16B illustrate the SEM photographsof the resist pattern after (B) the film deposition process inComparative Example 1 is performed. FIGS. 16A and 16B are thephotographs (left-hand side) of the cross section of the resist patternfrom the slanting upper part and the front part, respectively, and thecorresponding schematic diagrams (right-hand side) of the resistpattern. The magnification of the photographs of FIGS. 16A and 16B isthe same as the magnification of the photographs of FIGS. 15A and 15B.

As is apparent from FIGS. 15A to 16B, the resist pattern in FIGS. 15Aand 15B is larger in size, and the difference between the top width andthe bottom of the resist pattern in FIGS. 15A and 15B is smaller. Thatis, the size relation of the width dimension of the resist patternbetween FIG. 15 and FIG. 16 remains unchanged. Therefore, in order toimprove the slimming of the resist pattern, the slimming process in thefilm deposition apparatus is superior to the slimming process in thecoater.

In the fine pattern forming method and the film deposition apparatus ofthis embodiment, after the slimming process of the resist pattern isperformed using the oxygen-containing gas in the process chamber, thesilicon oxide can be formed supplying alternately the source gas and theoxygen radical-containing organic silicon to the same process chamber.Therefore, the silicon oxide can be formed keeping the surface of theresist pattern pure, and uniformity in the surface of the semiconductorsubstrate of the configuration with the fine patterns having a pitchbelow the resolution limit can be made better. Since the processes whichuse the processing unit which carries out slimming process of the resistpattern are reducible, the cost of the process which forms fine patternscan be reduced.

In this embodiment, although the case where the amino silane gas (BTBAS)is used is explained, in a case where another amino silane gas is usedas the Si source gas containing organic silicon, or ethoxy silane gas isused, the process can be performed in a similar manner.

Next, with reference to FIG. 17, the film deposition apparatus used forthe fine pattern forming method and the fine pattern forming method ofthe second embodiment will be described.

FIG. 17 is a vertical cross-sectional view illustrating the structure ofa film deposition apparatus used for the fine pattern forming method ofthis embodiment. The film deposition apparatus used for the fine patternforming method of this embodiment is different from the film depositionapparatus in the first embodiment in that it is provided with anozone-containing gas supplying device.

As illustrated in FIG. 17, the basic structure of the film depositionapparatus 80 a used for the fine pattern forming method of thisembodiment is the same as that of the film deposition apparatusillustrated in FIG. 3, and the film deposition apparatus 80 a includesthe oxygen-containing gas supplying device 14, the Si source gassupplying device 15 and the plasma generating device 30, and the filmdeposition apparatus 80 a is arranged to perform the film depositionthat is the same as the film deposition of the silicon oxide 104 in thefirst embodiment.

On the other hand, the film deposition apparatus 80 a is provided withan ozone-containing gas supplying device 14 a. The ozone-containing gassupplying device 14 a is provided with an ozone-containing gas supplysource 17 a, and the ozone-containing gas supply source 17 a isconnected to an oxygen-containing gas piping 18 via a flow controldevice 18 d and an opening and closing valve 18 c. Thereby, theozone-containing gas can be supplied to the process chamber 1.

In the case of the slimming process, the ozone-containing gas, forexample, ozone gas, is used. When performing the slimming process usingthe ozone gas, it is not necessary to generate the plasma. For thisreason, the ozone-containing gas is in the condition when nohigh-frequency voltage is applied to the plasma electrode 33 in theplasma generating device 30, and what is necessary is just to supply theozone-containing gas to the process chamber 1 via the distributed nozzle19.

In the film deposition apparatus 80 a used for the fine pattern formingmethod of this embodiment, the ozone-containing gas supplying device 14a is provided in addition to the oxygen-containing gas supplying device14, the Si source gas supplying device 15, and the plasma generatingdevice 30. After the slimming process of the resist pattern is performedusing the ozone-containing gas in the process chamber 1, silicon oxidecan be formed by supplying alternately the source gas and the oxygenradical-containing organic silicon in the same process chamber 1.Therefore, silicon oxide can be formed while keeping the surface of theresist pattern pure, and uniformity in the surface of the semiconductorsubstrate of the configuration of fine patterns having a pitch below theresolution limit can be made better.

Since the processes which use the processing unit which performs theslimming process of the resist pattern are reducible, the cost of theprocess which forms the fine patterns can be reduced.

Next, with reference to FIGS. 18 to 19J, a fine pattern forming methodof a third embodiment of the invention will be described.

FIG. 18 is a flowchart for explaining the procedure of respective stepsof the fine pattern forming method of this embodiment. FIGS. 19A to 19Jare cross-sectional views illustrating the configuration of the finepattern in each of the respective steps of the fine pattern formingmethod of this embodiment.

The configuration of the fine pattern after the steps S21 to S30 of FIG.18 are performed is equivalent to the configuration illustrated in FIGS.19A to 19J. The fine pattern forming method of this embodiment isdifferent from the first embodiment, which applies the film depositionprocess of the silicon oxide to the SWT process, in that it applies thefilm deposition process of the silicon oxide to the pattern organic filmto the LLE process.

As illustrated in FIG. 18, the fine pattern forming method of thisembodiment includes a process which forms a thin film and a coating, aprocess which forms a resist film, a patterning process, a slimmingprocess, and a film deposition process, and further includes a processwhich forms a coating, a process which forms a resist film, a patterningprocess, a slimming process, and an etching step.

Namely, the process which forms a thin film includes step S21 and theprocess which forms a resist film includes a first step S22 and a secondstep S27. The patterning process includes a first step S23 and a secondstep S28. The slimming process includes a first step S24 and a secondstep S29, the film deposition process includes step S25, and the etchingstep includes step S30.

Step S21 is a process which forms a thin film and a coating on asemiconductor substrate. FIG. 19A is a cross-sectional view illustratingthe configuration of the fine pattern after the step S21 is performed.

In step S21, as illustrated in FIG. 19A, the thin film 152 is formed onthe semiconductor substrate 151. The thin film 152 may be a film whichwill be processed later into fine patterns, and the thin film 152 may bean insulating layer of SiN or SiO2, and may be an electric conductionfilm such as conductive polysilicon. That is, the material of the thinfilm 152 is not limited, and the film which contains silicon nitride,silicon oxide, oxynitriding silicon, amorphous silicon, or polysiliconcan be used for it. In this example, the thin film 152 of SiN is used.

Subsequently, on the thin film 152, acid resisting material is appliedand the coating (BARC) 153 is formed. Similar to the first embodiment,the semiconductor substrate 151 is not limited a silicon substrate, andmay contain the structure in which the electric conduction filmcorresponding to the semiconductor chip or integrated circuit pattern isformed in the semiconductor substrate or on the semiconductor substrate.The thin film of this embodiment is equivalent to the film to be etchedin the claims.

Step S22 is a process which forms photoresist film 154. FIG. 19B is across-sectional view illustrating the configuration of the fine patternafter the step S12 is performed. As illustrated in FIG. 19B, thephotoresist is applied and the photoresist film 154 is formed on thecoating 153. The photoresist film 154 of this embodiment is equivalentto the first resist film in the claims.

Next, the patterning process containing step S23 is performed. Step S23is a process which forms resist pattern 154 a which exposes and developsformed photoresist film 154 and includes the photoresist film 154. FIG.19C is a cross-sectional view illustrating the configuration of the finepattern after the step S23 is performed. As illustrated in FIG. 19C, thephotoresist film is processed into resist patterns 154 a having apredetermined pitch p1 by using the photolithographic technique.

In this embodiment, the predetermined pitch p1 is made into theresolution limit of the exposure device as an example of the resistpattern 154 a. The resist pattern 154 a and the patterning process (stepS23) of this embodiment are equivalent to the first resist pattern andthe first patterning process in the claims, respectively. The pitch p1of this embodiment is equivalent to the first pitch in the claims.Therefore, the patterning process (first patterning process) of step S23is a process processed into the first resist pattern that arranges aresist film in the first pitch by using the photolithographic technique.

Next, the slimming process containing step S24 is performed. Step S24 isa process which forms resist pattern 154 b which carries out theslimming process of the resist pattern 154 a which includes thephotoresist film 154, and includes the photoresist film 154 (the firstslimming process). FIG. 19D is a cross-sectional view illustrating theconfiguration of the fine pattern after the step S24 is performed. Thetemperature is in a range of room temperature to 100 degree C. Themethod of the slimming process is not limited, and an example of theconditions of the slimming process may include the oxygen radical or theozone gas. The slimming process (step S24) of this embodiment isequivalent to the first slimming process in the claims.

In this embodiment, step S24 is performed within the process chamber ofthe film deposition apparatus for performing the film deposition processof step S25 performed continuously after that.

Next, the film deposition process including the step S25 is performed.Step S25 is a process which forms the thin film 152, the coating 153,and the SiO2 film 155 that is different in the resist pattern 154 b onthe coating 153 and the resist pattern 154 b, after the end of theslimming process. FIG. 19E is a cross-sectional view illustrating theconfiguration of the fine pattern after the step S25 is performed.

In the step S25, the SiO2 film 155 is formed in order to protect theresist pattern 154 b in the second photolithography process which willbe performed later. The SiO2 film 155 is formed on the coating 153 andthe resist pattern 154 b after the end of the slimming process, bysupplying alternately the source gas and the oxygen radical containingorganic silicon. The film deposition process in the film depositionprocess in this embodiment is also called a hardening process. The SiO2film is equivalent to the silicon oxide in the claims. It may be a filmof another material containing silicon and oxygen, such as a SiOx film,instead of SiO2 film. An oxynitriding silicon film (SiON film) can alsobe used.

Next, the second photolithography of step S26 to step S28 is performed.Step S26 is a process which forms a coating. FIG. 19F is across-sectional view illustrating the configuration of the fine patternafter the step S21 is performed.

In step S26, as illustrated in FIG. 19F, acid resisting material isapplied and the coating (BARC) 156 is formed on the SiO2 film 155. StepS26 can be skipped. When step S26 is skipped, the coating 153 formed instep S21 functions as a coating in the case of the exposure in step S28which is a patterning process which is the second time.

Step S27 is a process which forms a photoresist film 157. FIG. 19G is across-sectional view illustrating the configuration of the fine patternafter the step S27 is performed.

As illustrated in FIG. 19G, on SiO2 film 155, photoresist is applied andthe photoresist film 157 is formed. The photoresist film 157 of thisembodiment is equivalent to the second resist film in the claims.

Next, the patterning process containing step S28 is performed. Step S28is a process which forms resist pattern 157 a which includes thephotoresist film 157 which exposes and develops formed photoresist film157 and has predetermined pitch p2. FIG. 19H is a cross-sectional viewillustrating the configuration of the fine pattern after the step S28 isperformed. At this time, the pitch of resist pattern 157 a is set to thepredetermined pitch p2. In this embodiment, the resist pattern 157 a isthe same line and space pattern as resist pattern 154 a by which theslimming process is performed by the first photolithography. The resistpattern 157 a is processed so that it may be arranged between the resistpatterns 154 b by which the slimming process is performed and the resistpattern 154 b and the resist pattern 157 a may be arranged alternately.The resist pattern 157 a and the patterning process (step S28) of thisembodiment are equivalent to the second resist pattern and the secondpatterning process in the claims, respectively. The pitch p2 of thisembodiment is equivalent to the second pitch in the claims and it isequal to the pitch p1 (the first pitch).

Next, the slimming process containing step S29 is performed. Step S29 isa process which forms the resist pattern 157 b which carries out theslimming process of the photoresist film 157 which forms the resistpattern 157 a, and includes the photoresist film 157 (the secondslimming process). FIG. 19I is a sectional view of the configuration ofthe fine pattern after the step S29 is performed.

The temperature is in a range of room temperature to 100 degree C. Themethod of the slimming process is not limited, and an example of theconditions of the slimming process contains the oxygen radical or theozone gas. In the second slimming process, the resist pattern whichincludes the resist patterns 154 b and 157 b is formed. The resistpattern is the pattern in which the patterns 154 b and 157 b arearranged alternately, and the pitch p3 thereof is smaller than the pitchp1 or p2, and, in this embodiment, the pitch 3 is equal to about onehalf of the pitch p1 or p2. Thus, the resist pattern which has pitchbelow a resolution limit can be formed by arranging alternately resistpatterns 154 b and 157 b formed independently. The slimming process(step S29) of this embodiment is equivalent to the second slimmingprocess in the claims. Step S29 may be performed within equipmentdifferent from the film deposition apparatus which may carry out theslimming process within the film deposition apparatus which formssilicon oxide.

Next, step S30 is performed. As illustrated in FIG. 19J, the resistpatterns 154 b and 157 b are used for the mask of etching, the coatings156 and 153, the SiO2 film 155, and the thin film 152 are etched, andprocessed into the fine pattern which is considered the desired thinfilm 152. The coating 156, the SiO2 film 155, and the coating 153 areetched by using as a mask the resist pattern (the first resist pattern)154 b into which the configuration is processed, and the resist pattern(the second resist pattern) 157 b into which the configuration isprocessed.

What is necessary is just to etch the SiO2 film 155 and the coating 153,when the coating 156 is omitted. Thereby, it arranges in pitch of theabbreviated half of predetermined pitch p1 (the first pitch), and themask pattern is formed which includes the photoresist film (the firstresist film) 154 and photoresist film (the second resist film) 157.

Next, the thin film (film to be etched) 152 is etched using the maskpattern, and the thin film pattern (etching film pattern which includesthe film to be etched) which includes the thin film 152 is formed. Sincethe pitch p4 of the thin film 152 processed by performing step S30 isalmost equal to the pitch p3 of resist patterns 154 b and 157 b, thepitch p4 of the fine pattern which includes the thin film 152 is made tobe below the resolution limit. Thus, in this embodiment, the finepatterns having a pitch below the resolution limit can be formed.

The film forming method, which includes the processes from the process(step S21), which forms the coating 153, to the process (step S30),which etches the SiO2 film 155 and the coating 153 and forms the maskpattern, is defined as the mask pattern forming method in the claims.

The film forming method, which includes the mask pattern forming methodand includes the processes from the process (step S21) which forms thethin film (film to be etched) 152, to the process (step S30) whichetches the thin film (film to be etched) 152, is defined as the finepattern forming method in the claims. As mentioned above, in the case ofthe hardening process (the film deposition process) in this embodiment,an oxygen radical is supplied to the film deposition apparatus whichperforms the hardening process, and the slimming process of the resistpattern is performed. By supplying alternately the source gas and theoxygen radical-containing organic silicon, and forming silicon oxide onthe resist pattern by which slimming process is performed, and a coatingof silicon oxide can be formed keeping the surface of a resist patternpure, and uniformity in the field of the semiconductor substrate of theconfiguration of a fine pattern of having pitch below a resolution limitcan be made better.

Since the processes which use the processing unit which carries outslimming process of the resist pattern are reducible, the cost of theprocess which forms a fine pattern can be reduced.

Next, with reference to FIG. 3, FIG. 5, and FIGS. 20A to 20F, a finepattern forming method of a fourth embodiment of the invention will bedescribed.

FIGS. 20A to 20F are diagrams for explaining the reaction on thesemiconductor substrate in the fine pattern forming method of thisembodiment when DIPAS is used as the Si source gas. The fine patternforming method of this embodiment is different from the first embodimentthat uses BTBAS for Si source gas in the point of using DIPAS for Sisource gas.

In this embodiment, it is the same as that of the first embodiment toload a wafer in a process chamber, to rotate a wafer boat, and toperform a slimming process (step S1 of FIG. 5). It is the same as thatof the first embodiment after a slimming process to perform the process(step S2 of FIG. 5) which purges the inside of a process chamber, beforestarting a film deposition process.

Next, a film deposition process is performed. The film depositionprocess includes the process (step S3 of FIG. 5) which supplies DIPASwhich is the Si source gas like the first embodiment, and the process(step S4 of FIG. 5) which supplies the oxygen radical. Through the Sisource gas piping 21 and the Si source gas dispersion nozzle 22 as inFIG. 3 in step S3 in this embodiment, DIPAS is supplied to the inside ofthe process chamber 1 from the gas discharge hole 22 a for the supplyingtime T3. Thereby, the Si source gas is made to stick to thesemiconductor wafer. The time T3 in a range of 1 to 600 sec isillustrated. The flow rate of DIPAS in a range of 10-10000 mL/min (sccm)is illustrated.

The pressure in the process chamber 1 in a range of 0.133-13300 Pa isillustrated. The substrate temperature, which is in a range of roomtemperature (25 degrees C.) to 700 degrees C., or desirably in a rangeof room temperature (25 degrees C.) to 500 degrees C., or more desirablyin a range of room temperature (25 degrees C.) to 300 degrees C., isillustrated.

In the process which supplies the oxygen radical of step S4, as theoxygen-containing gas from the oxygen-containing gas supply source 17 ofthe oxygen-containing gas supplying device 14, the O2 gas is dischargedfrom the gas discharge hole 19 a via the oxygen-containing gas piping 18and the oxygen-containing gas dispersion nozzle 19. At this time, the RFgenerator 35 of the plasma generating device 30 is turned ON, a highfrequency electric field is formed, and the oxygen-containing gas (theO2 gas) is turned into a plasma state by the high frequency electricfield. The oxygen-containing gas in plasma state is supplied to theprocess chamber 1. The SiO2 film in which the Si source adsorbed by thesemiconductor wafer W is oxidized is formed. The time T4 in a range of 1to 600 sec is illustrated. Although the flow rate of theoxygen-containing gas varies depending on the number of sheets ofsemiconductor wafers W loaded, the flow rate in a range of 0.1-20000mL/min (sccm) is illustrated. The frequency of the RF generator 35 whichis 13.56 MHz is illustrated and the power of the RF generator 35 in arange of 10-1500 W is used. The pressure in the process chamber 1 in arange of 0.133-13300 Pa is illustrated.

Step S5 is performed between step S3 and step S4 as illustrated in FIG.5. Step S5 is the same as that of the first embodiment, and by repeatingand supplying the Si source gas and the oxygen inclusion plasma as theoxygen radical alternately in step S5 between step S3 and step S4, SiO2thin films can be can be laminated to reach the predetermined thickness.

The example of the reaction at this time is illustrated in FIG. 20. Asillustrated in FIG. 20, while the Si source gas is supplied betweenprocesses S3 (i.e., a process chamber), as illustrated in FIG. 20B fromthe condition illustrated in FIG. 20A, the supplied DIPAS reacts withthe surface of the semiconductor wafer W, and Si sticks to the surfaceof the semiconductor wafer W. Because DIPAS used as the source gas isthe monovalent amino silane, the inclusion of nitrogen (N) in theprecursor in which DIPAS is adsorbed in step S3 is difficult, and theinclusion of nitrogen in the resulting silicon oxide is difficult. Forthis reason, a good silicon film can be formed.

Because DIPAS used as the source gas is the monovalent amino silane, astructural impediment will not arise in the case of Si adsorption. Forthis reason, the rate of adsorption will not decrease and theproductivity will not fall.

Because DIPAS is used for the source gas, the thermal stability is goodand the flow control can be easily performed. The existing device of theconventional source supplying method may be used in a flexible manner.

Next, while an oxygen radical is supplied between processes S4 (i.e., aprocess chamber), as Si which adsorbed on semiconductor wafer W oxidizesand it is illustrated in FIG. 20D from the condition illustrated in FIG.20C, silicon oxide is formed on semiconductor wafer W. As illustrated inFIG. 20A and FIG. 5, when repeating step S3 and step S4 in step S5, thesilicon oxide is further formed by oxidizing Si which the surface ofsemiconductor wafer W is adsorbed in DIPAS, and Si is made to stick toas illustrated in FIG. 20F, and is adsorbed. As a result, the siliconoxide of a requested thickness is formed on the semiconductor wafer W.

Also in the fine pattern forming method using DIPAS which can form agood silicon film in this embodiment as Si source gas, the slimmingprocess which is performed with the resist coater, the slimming processand the film deposition process can be continuously processed by usingthe process chamber of the film deposition apparatus for performing theslimming process. Therefore, since the processes which use theprocessing unit to carry out slimming process of the resist pattern arereducible, the cost of the process which forms a fine pattern can bereduced.

Next, a fine pattern forming method of a fifth embodiment of theinvention will be described with reference to FIGS. 21 to 27B.

FIG. 21 is a flowchart for explaining the procedure of respective stepsof the fine pattern forming method of this embodiment. FIGS. 22A and 22Bare cross-sectional views illustrating the configuration of the finepattern in each process of the fine pattern forming method of thisembodiment. The configuration of the fine pattern, after the steps S111to S118 of FIG. 21 are performed, is equivalent to the configurationillustrated in FIGS. 22A to 22H.

The fine pattern forming method of this embodiment is replaced withsilicon oxide as an oxide film, and is different from the firstembodiment in that it forms an aluminum oxide film. The fine patternforming method of this embodiment includes: the process which forms athin film on a semiconductor substrate as illustrated in FIG. 21; theformation process which forms a resist film on a thin film; thepatterning process processed into the resist pattern (the first resistpattern (line part)) which arranges a resist film in the first pitch byusing the photolithographic technique (first patterning process); theslimming process of processing the configuration of the first resistpattern (first slimming process); the film deposition process whichforms an aluminum oxide film at room temperature on the resist pattern(the first resist pattern) into which source gas and the oxygen radicalare supplied and the configuration is processed according to theslimming process (first slimming process), and a thin film; the etchingstep; and the process which removes a resist pattern and etches anorganic film.

The process in which the process which forms a thin film forms a resistfilm including the step S111 includes the step S112. As for a patterningprocess, a slimming process includes the step S114 including the stepS113. As for a film deposition process, an etching step removes a resistpattern including the step S116 including the step S115, and the processwhich etches an organic film includes the step S117.

The etching step in FIG. 21 is equivalent to the oxide film etching stepin the claims. In this embodiment, as it is different from the firstembodiment and is illustrated in FIG. 21, although consecutiveprocessing may be performed within the same chamber (process chamber),the same chamber (process chamber) inner consecutive processing of thestep S114 and step S115 does not have to be performed. Since consecutiveprocessing does not have to be performed within the same chamber(process chamber), it is not necessary to generate the plasma in thechamber when forming the aluminum oxide film. The ashing of the resistfilm is performed by the plasma and the configuration does not change.

Step S111 is a process which forms a thin film on a semiconductorsubstrate, and is the same as step S11 of the first embodiment. FIG. 22Ais a cross-sectional view illustrating the configuration of the finepattern after the step S111 is performed.

In step S111, as illustrated in FIG. 22A, a thin film 202 and an organicfilm 203 are formed sequentially from the bottom on the semiconductorsubstrate 201. The semiconductor substrate 201, the thin film 202, andthe organic film 203 are the same as in the first embodiment.

The thin film and the organic film of this embodiment are equivalent tothe film to be etched and the coating in the claims, respectively. Thematerial of the thin film 202 is not limited, and the film whichcontains silicon nitride, silicon oxide, oxynitriding silicon, amorphoussilicon, or polysilicon can be used for it.

Step S112 is a process which forms photoresist film 204, and is the sameas step S12 in the first embodiment. FIG. 22B is a cross-sectional viewillustrating the fine pattern configuration after step S112 isperformed. The photoresist film 204 is the same as the photoresist film104 in the first embodiment.

Next, the patterning process containing step S113 is performed. StepS113 is a process which forms a resist pattern 204 a (line part) whichexposes and develops the formed photoresist film 204 and includes thephotoresist film 204, and is the same as step S13 in the firstembodiment. FIG. 22C is a cross-sectional view illustrating the finepattern configuration after the step S113 is performed.

As illustrated in FIG. 22C, it has line width LL4 of a line part, andthe space width SS4, and the resist pattern 204 a which includes thephotoresist film 204 is formed. In this embodiment, it has line widthLL4 and each line which constitutes a resist pattern is defined as aline part. Therefore, the patterning process of this embodiment is aprocess processed into the resist pattern which contains the line partwhich arranges a resist film in the predetermined pitch by using thephotolithographic technique.

Next, the slimming process containing step S114 is performed. Step S114is a process which forms resist pattern 204 b (line part) which carriesout the slimming process of the resist pattern 204 a which includes thephotoresist film 204, and includes the photoresist film 204, and is thesame as step S14 in the first embodiment. FIG. 22D is a cross-sectionalview illustrating the configuration of the fine pattern after the stepS114 is performed.

In this embodiment, the slimming process may take place within theprocess chamber of the film deposition apparatus for performing the filmdeposition process of step S115 continuously performed after that instep S114 like the first embodiment. The slimming process may take placewithin the process chamber of the film deposition apparatus forperforming the film deposition process of step S115, and a differentprocess chamber.

The method of slimming process can be performed like the firstembodiment, and the line width LL1 of resist pattern 204 b and the spacewidth SS1 which are made by carrying out the slimming process are set toLL1<LL4, SS1>SS4.

Next, the film deposition process containing step S115 is performed.Step S115 is a film deposition process which forms the Al2O3 film 205 onthe organic film 203 and the resist pattern 204 b after the end of theslimming process is performed. FIG. 22E is a cross-sectional viewillustrating the configuration of the fine pattern after the step S115is performed. The Al2O3 film (aluminum oxide film) is equivalent to thealuminum oxide film in the claims. The film may be a film of otherpresentations which make the AlOx film and contain aluminum and oxygenas a principal component instead of the Al2O3 film. Alternatively, filmscan be formed at room temperature, and as long as the film is an oxidefilm which does not damage the resist pattern at the time of filmdeposition, the oxide film of metals other than aluminum may be used.

Since the film deposition process of the Al2O3 film 205 performs afterweak photoresist film 204 has remained in the elevated temperatures asresist pattern 204 b, it is preferred to form films at low temperature.As a method for film deposition, if films can be formed at lowtemperatures, low-temperature MLD cannot perform the thing limitedespecially but this embodiment.

As a result, as illustrated in FIG. 22E, the location in which resistpattern 204 b is formed, and the location which is not formed areincluded. The Al2O3 film 205 is formed in an entire substrate, and theAl2O3 film 205 is formed so that the side face of resist pattern 204 bmay be covered also on the side face of resist pattern 204 b. If thethickness of the Al2O3 film 205 at this time is set to D, the width ofthe Al2O3 film 205 which covers the side face of the resist pattern 204b is also set to D, and one can set D to 30 nm.

Next, the film deposition process of the Al2O3 film by thelow-temperature MLD will be described. In the low-temperature MLD, thesource gas containing aluminum is supplied to the process chamber, andthe process which makes an aluminum material adsorb on the substrate,and the process which supplies the gas containing the ozone gas to theprocess chamber and oxidizes the aluminum material are repeatedalternately.

In the process which makes the source gas containing aluminum adsorb onthe substrate, via the supplying nozzle of aluminum material gas,trimethylaluminum (TMA) as the source gas containing aluminum issupplied to the process chamber for a predetermined time (indicated byT3′ in FIG. 25). Thereby, TMA is made to adsorb on the substrate.

Next, via the gas supply nozzle for the ozone gas in the process whichsupplies the gas containing the ozone gas is supplied to the processchamber and oxidizes the aluminum material for a predetermined time(indicated by T4′ in FIG. 25). The TMA adsorbed on the substrate isoxidized and the Al2O3 film 205 is formed.

When changing the process which makes the source gas which contains thealuminum mentioned above like the first embodiment adsorb on asubstrate, and the process which supplies the highly oxidizing gas tothe process chamber and oxidizes the aluminum material is performedbetween the processes. In order to remove the remaining gas in the lastprocess, the process which supplies the purge gas which includes inertgas, such as N2 gas, in the process chamber can be performed for apredetermined time (indicated by T5 in FIG. 25), in order to perform theevacuation of the inside of the process chamber.

In this embodiment, the source gas which contains an organoaluminumcompound as the Al source gas for forming the Al2O3 film 205 is used.The example of the Al source gas containing the organoaluminum compoundis trialkylaluminum.

Examples of trialkylaluminum may include TMA (trimethyl aluminum), TEAL(triethyl aluminum), TIBA (tri-isobutyl aluminum), DEAC (diethylaluminum chloride), EASC (ethylaluminum sesquichloride), EADC(ethylaluminum di-chloride), and TNOA (tri-n-octyl aluminum).

Examples of the highly oxidizing gas may include O3 gas (ozone gas) andwater vapor generation (WVG) gas. Examples of WVG gas may include a gascontaining H2O gas (steam), a gas containing steam generated from H2 gas(hydrogen gas) and O2 gas (oxygen gas) which are mixed beforehand at anelevated temperature, and a gas saturated with steam which is generatedby underwater bubbling of H2 gas (hydrogen gas) or O2 gas (oxygen gas).

Next, an etching step including the step S116 is performed. Step S116 isan etching step etched so that the Al2O3 film 205 may remain only as thewall part 205 a of resist pattern 204 b (etch back), and S116 is thesame as step S16 in the first embodiment.

FIG. 22F is a cross-sectional view illustrating the configuration of thefine pattern after the step S116 is performed.

The third pattern 206 that includes the resist pattern 204 b and thewall part 205 a is formed. When line width of the third pattern 206 isset to LL3 and the space width is set to SS3, it is LL3=LL1+D×2 andSS3=LL1+SS1−LL3. By performing the etching step, the oxide film isetched to remain as side walls on the side faces of the line part of theresist pattern after the slimming process is performed.

The etching step is a process which etches the oxide film to remain asside walls on the side faces of the line part of the resist patternafter the slimming process is performed. Step S117 includes a processwhich removes the resist pattern 204 b and forms the wall parts 205 a,and a process which etches the organic film 203 by using as a mask theformed wall parts 205 a.

Namely, in step S117, the aluminum oxide film may remain as side wallson the side faces of the resist pattern (the first resist pattern (linepart)). It is an oxide film etching step which etches an aluminum oxidefilm, and is the same as that of step S17 in the first embodiment. FIG.22G is a cross-sectional view illustrating the configuration of the finepattern after step S117 is performed.

The second pattern 207 in which the line width is equal to D and thespace width LL1 and the space width SS3 appear alternately is formed.Similar to the first embodiment, the space width can be set to SS2 equalto LL1 or SS3, and the line width equal to D can be set to LL2. Thesecond pattern 207 includes the wall part 205 a and the organic film(coating) 203, and is equivalent to the mask pattern in the claims.Then, it is the same as that of the first embodiment to use the secondpattern 207 as a mask, and to etch the thin film 202. That is, step S118is performed.

In step S118, the thin film (film to be etched) 202 is processed usingthe second pattern (mask pattern) 207, and as illustrated in FIG. 22H,the pattern 202 a which includes the thin film (film to be etched) 202is formed.

The organic film (coating) 203 may remain in the upper part of thepattern 202 a. The etching of the thin film 202 may be performed using agas containing CF base gas, CHF base gas, CH base gas, or oxygen gas.

The film forming method which includes the processes from the process(step S111) which forms the organic film (coating) 203 to the process(step S117) which forms the mask pattern which includes the wall part205 a and the organic film (coating) 203 is defined as the mask patternforming method in the claims.

The film forming method which includes the mask pattern forming methodand includes the processes from the process (step S111) which forms thethin film (film to be etched) 202 to the process (step S118) which formsthe pattern 202 a from the thin film (film to be etched) 202 is definedas the fine pattern forming method in the claims.

Next, with reference to FIG. 3 and FIGS. 4, 23 and 24, the filmdeposition apparatus used for the fine pattern forming method of thisembodiment will be described. FIG. 23 is a vertical cross-sectional viewillustrating the structure of the film deposition apparatus used for thefine pattern forming method of this embodiment. FIG. 24 is across-sectional view illustrating the typical structure of the filmdeposition apparatus used for the fine pattern forming method of thisembodiment. The heating apparatus is omitted in FIG. 24.

When performing the film deposition process of this embodiment using thefilm deposition apparatus 80 illustrated in FIGS. 3 and 4, consecutiveprocessing of the slimming process and the film deposition process canbe performed in the same film deposition apparatus.

On the other hand, in this embodiment, the film deposition apparatuswhich has a process chamber which is different from the process chamberwhich is used to perform the slimming process. The example of the filmdeposition apparatus is illustrated in FIGS. 23 and 24.

The film deposition apparatus 80 b illustrated in FIGS. 23 and 24removes the plasma generating device 30 and the relevant portion in thefilm deposition apparatus 80 illustrated in FIGS. 3 and 4. In FIGS. 23and 24, the elements which are the same as corresponding elements of thefilm deposition apparatus 80 in FIGS. 3 and 4 are designated by the samereference numerals, and a description thereof will be omitted.

On the other hand, instead of the oxygen-containing gas supplying device14 of the film deposition apparatus 80, the ozone gas supplying device14 b is formed in the film deposition apparatus 80 b. The gaseous ozonepiping 18 e through which the ozone gas supplying device 14 b draws theozone gas from the ozone gas supply source 17 b and the ozone gas supplysource 17 b, connects with the ozone gas piping 18 e, and has the ozonegas dispersion nozzle 19 b which includes the quartz tube whichpenetrates the side attachment wall of the manifold 3 to the inside, isbent upward, and extends vertically. Two or more gas discharge holes 19c are separated with a predetermined spacing in the vertical portion ofthe ozone gas dispersion nozzle 19 b, it can be formed in it, anddischarge of the ozone gas can be horizontally performed uniformlytowards the process chamber 1 b from each gas discharge hole 19 c.Instead of the Si source gas supplying device 15 of the film depositionapparatus 80, the Al source gas supplying device 15 b is formed in thefilm deposition apparatus 80 b. The Al source gas supplying device 15 bincludes the Al source gas supply source 20 b, the Al source gas piping21 c which draws the Al source gas from the Al source gas supply source20 b, connects with the Al source gas piping 21 c, and has the Al sourcegas dispersion nozzle 22 b which includes the quartz tube whichpenetrates the side attachment wall of manifold 3 to the inside, is bentupward, and extends vertically. Along the device direction, two or moregas ejection holes 22 c are separated with a predetermined spacing forthe Al source gas dispersion nozzle 22 b, and it is formed in it.Discharge of the Al source gas which contains an organoaluminum compoundin the process chamber 1 b horizontally from each gas discharge hole 22c can be performed.

As illustrated in FIG. 24, the two Al source gas dispersion nozzles 22 bmay be formed. Alternatively, only one Al source gas dispersion nozzlemay be provided. The gaseous ozone supplying device 14 b is equivalentto the oxygen radical supplying unit in the claims, and the Al sourcegas supplying device 15 b is equivalent to the source gas supplying unitin the claims. The ozone gas piping 18 e, the Al source gas piping 21 c,the purge gas piping 24, the valves 18 f, 21 d, and 24 a and the flowcontrol devices 18 g, 21 e and 24 b are formed, and can supply the ozonegas, the Al source gas, and the purge gas, respectively. The componentequivalent to the plasma generating device 30 which forms the plasma ofoxygen-containing gas with film deposition apparatus 80 is not providedin the film deposition apparatus 80 b.

Next, with reference to FIG. 25, the process in the slimming process andfilm deposition process of a fine pattern forming method of thisembodiment will be described. FIG. 25 is a diagram for explaining thefine pattern forming method in this embodiment, and is a timing chartwhich illustrates the timing of supplying of the gas in a slimmingprocess and a film deposition process. The timing of supplying of thegases in the slimming process and the film deposition process of thefine pattern forming method of this embodiment is as illustrated in FIG.25. Except for the fact that the Si source gas is replaced with theoxygen-containing gas using the Al source gas, and the plasma is notused in the film deposition process using the ozone gas, the processesare the same as those of the first embodiment. Steps S1 and S2 are thesame as those of the first embodiment.

However, in carrying out steps S1 and S2 using the film depositionapparatus which does not have the plasma generating device whichillustrates the film deposition process in FIGS. 23 and 24, step S1 isperformed within another process chamber which has the plasma generatingdevice, a wafer is carried to the film deposition apparatus in step S2,and the purge gas is supplied. Then, step S3′ which supplies the Alsource gas containing an organoaluminum compound to the process chamber1 b and the aluminum source is made to stick to the substrate, and stepS4′ which supplies the ozone gas to the process chamber 1 b and oxidizesthe Al source gas are repeated alternately.

In this embodiment, in step S3′, via the Al source gas piping 21 c andthe Al source gas dispersion nozzle 22 b, TMA as the Al source gas fromthe Al source gas supply source 20 b of the Al source gas supplyingdevice 15 b is supplied to the inside of the process chamber 1 b fromthe gas discharge hole 22 c at the time T3′. Thereby, the Al source gasis made to stick to the semiconductor wafer. The time T3′ in a range of1 to 600 sec is illustrated. The flow rate of the Al source gas in arange of 10-500 mL/min (sccm) is illustrated. The pressure in theprocess chamber 1 b in a range of 13.3-665 Pa is illustrated.

The ozone gas is discharged from the gas discharge hole 19 c in theprocess which supplies the ozone gas of step S4′ via the ozone gaspiping 18 e and the ozone gas dispersion nozzle 19 b from the ozone gassupply source 17 b of the ozone gas supplying device 14 b. The Al2O3film in which the aluminum source adsorbed by the semiconductor wafer Wis oxidized is formed. The time T4′ in a range of 1 to 600 sec isillustrated. The flow rate of the ozone gas in a range of 100-20000mL/min (sccm) is illustrated. The pressure in the process chamber 1 b ina range of 13.3-665 Pa is illustrated.

It can replace with the ozone gas and the steam oxidation raw gasmentioned above can be used. Step S5 which is performed between step S3′and step S4′ is the same as that of the first embodiment. If the filmdeposition process in this embodiment is performed, the source gas whichcontains the organoaluminum compound as the aluminum source will beused. Since the reaction advances by supplying the ozone gas or steamoxidation raw gas without raising the temperature in the oxidationprocess, the Al2O3 film can be formed at a low temperature, such as 100degrees C. or less or at room temperature.

In this embodiment, the slimming process and the film deposition processare performed within the same process chamber of the film depositionapparatus, and it is possible to reduce the cost of the processes as inthe first embodiment.

Next, with reference to FIG. 26 and FIG. 34, in this embodiment, theconfiguration of the resist pattern processed at the slimming processdoes not change before and after the film deposition process. Bymeasuring the width dimensions of the resist pattern after the filmdeposition process, the evaluation result will be described.

FIGS. 26A and 26B are photographs and schematic diagrams of the resistpatterns after the aluminum oxide films in Example 2 and ComparativeExample 2 are formed.

In Example 2, the Al source gas and the ozone gas are suppliedalternately on the resist pattern after performing the slimming process,and the film deposition process which forms the aluminum oxide film isperformed. The Si source gas and the oxygen-containing gas plasma aresupplied alternately on the resist pattern after performing a slimmingprocess as Comparative Example 2, and the film deposition process whichforms silicon oxide is performed. The film deposition conditions of thefilm deposition process in Example 2 and Comparative Example 2 areillustrated below.

Example 2

(1) Source Gas Supplying Conditions

-   Source gas: TMA-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 39.9 Pa-   Gas mass flow: 100 sccm-   Supplying time: 5 sec    (2) Oxidizing Gas Supplying Conditions-   Oxidizing gas: ozone gas+oxygen gas-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 133 Pa-   Ozone gas flow rate: 200 g/m3-   Oxygen gas mass flow: 10.0 slm-   Supplying time: 15 sec    (3) Repetition Conditions-   Sum cycle: 210 cycles

Comparative Example 2

(1) Source Gas Supplying Conditions

-   Source gas: DIPAS (LTO520)-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 26.7-227 Pa-   Gas mass flow: 50-1000 sccm-   Supplying time: 1-10 sec    (2) Oxidizing Gas Supplying Conditions-   Oxidizing gas: oxygen gas-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 66.7-227 Pa-   Gas mass flow: 5-30 slm-   Supplying time: 5-30 sec-   RF generator frequency: 13.56 MHz-   RF generator power: 50-500 W    (3) Repetition Conditions-   Total cycle: 140-150 cycles

As illustrated in FIGS. 26A and 26B, the thickness of the oxide film isset to D. The height dimension of the resist pattern is set to H, thetop width dimension of the resist pattern is set to T, the widthdimension of the resist pattern in the location of an intermediateheight, which is half of the height from the bottom to the top, is setto M, and the bottom width dimension of the resist pattern is set to B.

Next, the dimensions H, T, M, B, and the ratio T/B of the top width andthe bottom width of the resist pattern obtained in Example 2 andComparative Example 2 are illustrated in FIG. 35.

As illustrated in FIG. 35, in Example 2 and Comparative Example 2, D is30 nm, respectively. As illustrated in FIG. 35, when the aluminum oxidefilm is formed, the decrement of the dimensions of the resist patternbefore and after the aluminum oxide film is formed in Example 2 issmaller than the decrement of the dimensions of the resist patternbefore and after the silicon oxide film is formed in Comparative Example2.

As illustrated in FIG. 35, when the aluminum oxide film is formed, theratio T/B of the top width and the bottom width of the resist patternincreases to be larger than in the case when the silicon oxide film isformed, and serves as the value near 1. That is, when the aluminum oxidefilm is formed, the difference between the top width and the bottomwidth can be smaller than in the case where the silicon oxide film isformed.

Next, with reference to FIGS. 27A-27B and FIG. 36, the effect ofdecreasing the damage (breakage) to the resist pattern processed at theslimming process at the film deposition process in this embodiment willbe described.

Examples 3 and 4 are illustrated. In Examples 3 and 4, the photoresistfilm is formed but the slimming process of the resist pattern is notperformed, and the thickness of the photoresist film after the oxidefilm is formed is measured and the measured thickness is compared withthat of Comparative Example 3. The evaluation result will be described.FIGS. 27A and 27B are cross-sectional views illustrating theconfiguration of the film for measuring the amount of ashing of theresists in Examples 3 and 4 and Comparative Example 3.

In Example 3, as illustrated in FIG. 27A, the photoresist film 204 whichis about 300 nm thick is formed on the semiconductor substrate 201, thethickness of the photoresist film 204 is measured, and this thickness isreferred to as HP1.

Next, the film deposition process which forms the Al2O3 film 205 on thephotoresist film 204 by supplying the Al source gas and the ozone gasalternately is performed. At this time, the supplying cycle at which theAl source gas and the ozone gas are supplied alternately is changed, andthe thickness HA of the Al2O3 film 205 is changed to 5 nm, 10 nm, 15 nmand 20 nm.

Next, the fluoric acid (HF) washing is performed, the Al2O3 film 205 isremoved, the thickness of the photoresist film 204 exposed to thesurface is measured, and this thickness is referred to as HP2. Theamount of ashing calculated from the amount of decrement of the resistthickness is set to a difference HP1-HP2 between HP1 and HP2.

It is assumed that (1) the source-gas supplying conditions and (2) theoxidizing-gas supplying conditions of Example 3 are the same as those ofExample 2, and (3) the repetition conditions are set to 35 to 140cycles.

In Example 4, instead of the ozone gas in Example 3, a steam oxidationraw gas is used. In Example 4, the thickness of the photoresist film 204exposed to the surface is measured for only the case in which thethickness HA of the Al2O3 film 205 is equal to 10 nm.

In Comparative Example 3, as illustrated in FIG. 27B, the photoresistfilm 104 which is about 300 nm thick is formed on the semiconductorsubstrate 101, the thickness of the photoresist film 104 is measured,and this thickness is referred to as HP1.

Next, the film deposition process which forms the SiO2 film 105 on thephotoresist film 104 by supplying the Si source gas and theoxygen-containing gas alternately is performed. The thickness of theSiO2 film 105 at this time is referred to as HS.

Next, the fluoric acid (HF) washing is performed, the SiO2 film 105 isremoved, the thickness of the photoresist film 104 exposed to thesurface is measured, and it is referred to as HP2. The amount of ashingcalculated from the amount of decrement of the resist thickness is setto a difference HP1-HP2 between HP1 and HP2 similar to Example 3.

It is assumed that (1) the source-gas supplying conditions and (2)oxidizing-gas supplying conditions of Comparative Example 3 are the sameas those of Comparative Example 2, and (3) the repetition conditions areset to 23 cycles or less.

Next, the thickness dimensions and the amount of ashing HP1-HP2 of theAl2O3 film obtained in Example 3, Example 4, and Comparative Example 3are illustrated in FIG. 36.

As illustrated in FIG. 36, when the aluminum oxide film is formed andthe ozone gas and the steam oxidation raw gas are used, the amount ofashing HP1-HP2 is smaller than in the case where the silicon oxide filmis formed. That is, the amount of ashing does not increase with theincrease of the film deposition time and film deposition thickness ofthe aluminum oxide film. Therefore, the ashing of the resist is notperformed by the film deposition of the aluminum oxide film. It appearsthat when the aluminum oxide film is formed, the oxygen plasma does notarise.

As mentioned above, apart from the first embodiment in which the siliconoxide film is formed, because the configuration of the resist patternafter the end of the slimming process in this embodiment does not changebefore and after the film deposition process, this embodiment has theeffect that the configuration of the resist pattern is preciselycontrollable.

As explained with reference to FIGS. 23 and 24, when performing theslimming process within a different process chamber from the filmdeposition apparatus which performs the film deposition process, theconfiguration of the resist pattern can be precisely controlled in thisembodiment.

Next, with reference to FIGS. 28 to 29J, a fine pattern forming methodof a sixth embodiment of this invention will be described.

FIG. 28 is a flowchart for explaining the procedure of each process ofthe fine pattern forming method of this embodiment. FIGS. 29A to 29J arecross-sectional views illustrating the configuration of the fine patternin each of the respective steps of the fine pattern forming method ofthis embodiment.

The configuration of the fine pattern after the steps S121 to S130 ofFIG. 28 are performed is equivalent to the configuration illustrated inFIGS. 29A to 29J. The fine pattern forming method of this embodiment isdifferent from the previously described third embodiment in that analuminum oxide film is formed instead of the silicon oxide film.

The fine pattern forming method of this embodiment includes, asillustrated in FIG. 28: the process which forms a thin film and acoating on a semiconductor substrate; the process which forms a resistfilm on the thin film and the coating; the patterning process whichprocesses the resist film into resist patterns arranged at a first pitch(the first resist pattern (line parts)) by using the photolithographictechnique (first patterning process); the slimming process (firstslimming process) of processing the configuration of the resist pattern(the first resist pattern); and the film deposition process which formsan aluminum oxide film at room temperature on the thin film and theresist pattern after the end of the slimming process (first slimmingprocess) by supplying the source gas and the oxygen-containing gas (thefirst resist pattern) to the process chamber. Thereafter, the processwhich forms a coating on the aluminum oxide film; the process whichforms a resist film (the second resist film), and the second patterningprocess using the photolithography technique are performed. In thesecond patterning process, the resist film (the second resist film) isprocessed into second resist patterns having a second pitch equal to thefirst pitch, and second resist patterns are shifted by half of the firstpitch so that the first resist patterns and the second resist patternsare arrayed alternately. Thereafter, the slimming process (secondslimming process) of processing the configuration of the second resistpatterns is performed, and the etching step is further performed.

The process which forms the thin film includes step S121, and theprocess which forms the resist film includes the first resist filmforming step S122 and the second resist film forming step S127. Thepatterning process includes the first patterning step S123 and thesecond patterning step S128. The slimming process includes the firstslimming step S124 and the second slimming step S129. The filmdeposition process includes the step S125 and the etching processincludes the step S130.

Step S121 is the same process as step S21 in the third embodiment, andas illustrated in FIG. 29A, the thin film 252 is formed on thesemiconductor substrate 251 in this step S121. The thin film 252 is afilm which will be processed into fine patterns later, and the thin film252 may be an insulating layer of SiN or SiO2, and may be an electricconduction film like conductive polysilicon. Similar to the thirdembodiment, the thin film 252 may an insulating layer of SiN. That is,the material of the thin film 252 is not limited, and a film whichcontains any of silicon nitride, silicon oxide, oxynitriding silicon,amorphous silicon, or polysilicon can be used as the thin film 252.Similar to the third embodiment, the semiconductor substrate 251 mayalso include a structure in which the electric conduction film and theinterlayer insulation film are formed. Similar to the third embodiment,the coating (BARC) 253 is formed on the thin film 252 by applying theacid resisting material. The thin film of this embodiment is equivalentto the film to be etched in the claims.

Step S122 is the same process as step S22 in the third embodiment, andas illustrated in FIG. 29B, the photoresist is applied and thephotoresist film 254 is formed on the coating 253. Step S123 is the sameprocess as step S23 in the third embodiment, and as illustrated in FIG.29C, by using the photolithography technique, the photoresist film 254is exposed and developed, and the resist patterns 254 a having apredetermined pitch p1 are formed.

The resist pattern 254 a and the patterning process (step S123) of thisembodiment are equivalent to the first resist pattern and the firstpatterning process in the claims, respectively. The pitch p1 of thisembodiment is equivalent to the first pitch in the claims. Therefore,the patterning process (first patterning process) of step S123 is aprocess processed into the first resist pattern that arranges a resistfilm in the first pitch by using the photolithographic technique.

Step S124 is the same process as step S24 in the third embodiment, andas illustrated in FIG. 29D, in this step S124, the slimming process ofthe resist patterns 254 a of the photoresist film 254 is performed toform the resist patterns 254 b of the photoresist film 254 (the firstslimming process). The method of the slimming process is not limited,and can be performed in the atmosphere containing the oxygen radical orthe ozone gas, and the temperature is in a range of room temperature to100 degrees C. The slimming process (step S124) of this embodiment isequivalent to the first slimming process in the claims.

Step S124 may be performed within the process chamber of the filmdeposition apparatus for performing the film deposition process of stepS125 performed continuously after that, and may be performed within aprocess chamber different from the film deposition apparatus forperforming the film deposition process of step S125.

Step S125 is the same process as step S25 in the third embodiment, andas illustrated in FIG. 29E, in this step S125, an Al2O3 film 255, whichis different from the thin film 252, the coating 253 and resist patterns254 b, is formed on the coating 253 and the resist patterns 254 b afterthe end of the slimming process. In the step S125, the Al2O3 film 255 isformed in order to protect the resist patterns 254 b from the secondphotolithography process which will be performed later. Similar to thefifth embodiment, by supplying alternately the source gas and the ozonegas (or steam oxidation raw gas) containing the organoaluminum compound,the Al2O3 film 255 is formed on the resist patterns 254 b after theslimming process is performed, and on the coating 253.

Similar to the third embodiment, the film deposition process of stepS125 may also be called hardening process. Similar to the fifthembodiment, the Al2O3 film 255 is equivalent to the aluminum, oxide filmin the claims, an AlOx film or other may be used instead as the Al2O3film 255, and the aluminum oxide film may be formed at room temperature.An oxide film of another metal other than aluminum may be used if itdoes not damage the resist patterns at the time of film deposition.

Step S126 is the same process as step S26 in the third embodiment, andas illustrated in FIG. 29F, in this step S126, the acid resistingmaterial is applied and the coating (BARC) 256 is formed on the Al2O3film 255. However, formation of the second coating 256 in step S126 maybe omitted after the end of step S125, and step S127 may be performed.

When step S126 is skipped, the coating 253 formed in step S121 functionsas a coating in the case of the exposure in step S128 which is thesecond patterning process.

Step S127 is the same process as step S27 in the third embodiment, andas illustrated in FIG. 29G, in this step S127, the photoresist isapplied and the photoresist film 257 is formed on the Al2O3 film 255.The photoresist film 257 of this embodiment is equivalent to the secondresist film in the claims.

Step S128 is the same process as step S28 in the third embodiment, andas illustrated in FIG. 29H, in this step S128, the formed photoresistfilm 257 is exposed and developed so that the resist patterns 257 a ofthe photoresist film 257 having a predetermined pitch p2 are formed. Atthis time, the pitch of resist patterns 257 a is equal to thepredetermined pitch p2.

In this embodiment, the resist patterns 257 a are the same as the lineand space patterns of the resist patterns 254 a formed by the firstphotolithographic process and the slimming process. Moreover, the resistpatterns 257 a are arranged between the resist patterns 254 b after theend of the slimming process so that the resist patterns 254 b and theresist pattern 257 a are arrayed alternately.

The resist pattern 257 a and the patterning process (step S128) of thisembodiment are equivalent to the second resist pattern and the secondpatterning process in the claims, respectively. The pitch p2 of thisembodiment is equivalent to the second pitch in the claims, which isequal to the pitch p1 (the first pitch).

Step S129 is the same as the step S29 in the third embodiment, and, asillustrated in FIG. 29I, this step is a process which performs theslimming process of the resist patterns 257 a of the photoresist film257 to form the resist patterns 257 b of the photoresist film 257 (thesecond slimming process).

The method of the slimming process is not limited, and can be performedin the atmosphere containing the oxygen radical or the ozone gas. Thetemperature is in a range of room temperature to 100 degrees C.

Step S129 may be performed within the process chamber of the filmdeposition apparatus for performing the film deposition process of stepS125, and may be performed within a process chamber different from thefilm deposition apparatus for performing the film deposition process ofstep S125. Of the second slimming process, the resist pattern whichincludes the resist patterns 254 b and 257 b is formed.

The resist pattern is a pattern in which the patterns 254 b and 257 bare arranged alternately, and the pitch p3 is smaller than the pitch p1or p2, and, in this embodiment, the pitch p3 is equal to about one halfof the pitch p1 or p2. Thus, the resist pattern which has a pitch belowthe resolution limit can be formed by arranging alternately the resistpatterns 254 b in the pitch p1 and arranging the resist patterns 257 bin the pitch p2 which is equal to the pitch p1.

The slimming process (step S129) of this embodiment is equivalent to thesecond slimming process in the claims. Step S129 may be performed withindifferent equipment from the film deposition apparatus which may carryout within the film deposition apparatus which forms an aluminum oxidefilm, or forms an aluminum oxide film.

Step S130 is the same as the step S30 in the third embodiment, and asillustrated in FIG. 29J, in this step S130, the resist patterns 254 band 257 b are used for the mask of etching, the coatings 256 and 253,the Al2O3 film 255, and the thin, film 252 are etched and processed intothe desired fine patterns of the thin film 252. The coating 256, theAl2O3 film 255, and the coating 253 are etched by using as a mask theresist pattern (the first resist pattern) 254 b into which theconfiguration is processed, and the resist pattern (the second resistpattern) 257 b into which the configuration is processed. What isnecessary is just to etch the Al2O3 film 255 and the coating 253, whenthe coating 256 is omitted. Thereby, it arranges in pitch of theabbreviated half of predetermined pitch p1 (the first pitch), and themask pattern which includes the photoresist film (the first resist film)254 and photoresist film (the second resist film) 257 is formed.

Next, the thin film (film to be etched) 252 is etched using the maskpattern, and the thin film pattern (etching film pattern which includesthe film to be etched) which includes the thin film 252 is formed. Sincethe pitch p4 of the thin film 252 processed by performing step S30 isalmost equal to the pitch p3 of the resist patterns 254 b and 257 b, thepitch p4 of the fine patterns which includes the thin film 252 is madeto be below the resolution limit. Thus, in this embodiment, the finepattern which has pitch below the resolution limit can be formed.

In this embodiment, the configuration of the fine pattern formed of theLLE process is more controllable to precision.

Next, with reference to FIGS. 30 to 33, a fine pattern forming method ofa seventh embodiment of the invention will be described.

FIG. 30 is a flowchart for explaining the procedure of each process ofthe fine pattern forming method of this embodiment. FIGS. 31A to 31C arecross-sectional views illustrating the configuration of the fine patternin each process of the fine pattern forming method of this embodiment.

The configuration of the fine pattern after the steps S211 to S218 ofFIG. 30 are performed is equivalent to the configuration illustrated inFIGS. 31A to 31I. The fine pattern forming method of this embodiment isdifferent from the fifth embodiment in that it forms a silicon oxidefilm as an oxide film after an aluminum oxide film is formed.

The fine pattern forming method of this embodiment as illustrated inFIG. 30 includes: the process which forms a thin film on a semiconductorsubstrate; the process which forms a resist film on the thin film; thepatterning process which processes the resist film into resist patternsarrayed at a first pitch (the first resist pattern (line part)) by usingthe photolithographic technique (first patterning process); the slimmingprocess of processing the configuration of the first resist patterns(first slimming process); the film deposition process which forms analuminum oxide film at room temperature on the thin film and the resistpatterns (the first resist patterns) after the end of the first slimmingprocess by supplying the source gas and the oxygen radical; the siliconoxide film deposition process which forms a silicon oxide film on thealuminum oxide film after the end of the film deposition process bysupplying the source gas and the oxygen radical containing organicsilicon; the oxide film etching step which etches the aluminum oxidefilm and the silicon oxide film so that the silicon oxide film and thealuminum oxide film remain as side wall parts on the side faces of theline parts of the resist pattern; and the process which removes theresist pattern and etches the organic film.

The process which forms the thin film includes the step S211 and theprocess which forms the resist film includes the step S212. Thepatterning process includes the step S213, the slimming process includesthe step S214, the film deposition process includes the step S215, thesilicon oxide film deposition process includes the step S216, theetching step includes the S217, the process which removes the resistpattern and etches the organic film includes the step S218, and theprocess which etches the thin film includes the step S219. The etchingstep in FIG. 30 is equivalent to the oxide film etching step in theclaims.

Similar to the fifth embodiment, as illustrated in FIG. 30, consecutiveprocessing of the step S214 and the step S215 does not have to beperformed within the same chamber (process chamber) in this embodiment.

Step S211 is the same process as step S111 in the fifth embodiment, andas illustrated in FIG. 31A, in this step S211, the thin film 302 and theorganic film 303 are formed on the semiconductor substrate 301sequentially from the bottom thereof. The semiconductor substrate 301,the thin film 302, and the organic film 303 are the same as in the fifthembodiment. The thin film and the organic film of this embodiment areequivalent to the film to be etched and the coating in the claims,respectively.

The material of the thin film 202 is not limited, and a film containingany of silicon nitride, silicon oxide, oxynitriding silicon, amorphoussilicon, or polysilicon can be used as the thin film 202.

Step S212 is the same process as step S112 in the fifth embodiment, andas illustrated in FIG. 31B, in this step S212, the photoresist film 304is formed. Step S213 is the same process as step S113 in the fifthembodiment, and as illustrated in FIG. 31C, in this step S213, theformed photoresist film 304 is exposed and developed, and the resistpattern 304 a of the photoresist film 304 is formed. Moreover, theresist pattern 304 a of the photoresist film 304 having the line widthLL4 and the space width SS4 is formed.

In this embodiment, each line which has the line width LL4 andconstitutes the resist pattern is defined as a line part. Therefore, thepatterning process of this embodiment is a process which processes theresist film into the resist patterns having the line parts arrayed at apredetermined pitch by using the photolithographic technique.

Step S214 is the same process as step S114 in the fifth embodiment, andas illustrated in FIG. 31D, in this step S214, the slimming process ofthe resist pattern 304 a of the photoresist film 304 is performed toform the resist pattern 304 b of the photoresist film 304.

Similar to the fifth embodiment, the step S214 in this embodiment may beperformed within the process chamber of the film deposition apparatuswhich is used to perform the film deposition process of step S215.Alternatively, the step S214 in this embodiment may be performed withina process chamber which is different from the process chamber of thefilm deposition apparatus which is used to perform the film depositionprocess of step S215.

The method of the slimming process may be performed similar to the fifthembodiment, and the line width LL1 and the space width SS1 of the resistpattern 304 b after the end of the slimming process are set to LL1<LL4and SS1>SS4.

As illustrated in FIG. 31E, step S215 is a film deposition process whichforms the Al2O3 film 305 a on the organic film 303 and the resistpatterns 304 b after the end of the slimming process. However, the Al2O3film 305 a is formed for covering the resist patterns 304 b and theorganic film 203, and the thickness of the Al2O3 film 305 a may besmaller than that of the Al2O3 film 205 in the fifth embodiment.

The thickness of the Al2O3 film 305 a is set to D1. The Al2O3 film(aluminum oxide film) may be a film of another material, such as an AlOxfilm instead of the Al2O3 film. The Al2O3 film 305 a is equivalent tothe aluminum oxide film in the claims. The film deposition process ofthe Al2O3 film 305 a may be performed similar to the fifth embodiment.

Step S216 is a process which is not included in the fifth embodiment,and as illustrated in FIG. 31F, this step S216 is a silicon oxide filmdeposition process which forms the SiO2 film 305 b on the Al2O3 film 305a after the end of the film deposition process of step S215. The siliconoxide film deposition process may be performed similar to the step S15in the first embodiment. The thickness of the SiO2 film 305 b is set toD2. The thickness

D of the sum of the lamination layer of the Al2O3 film 305 a and theSiO2 film 305 b is set to D=D1+D2. The width of the lamination layer ofthe Al2O3 film 305 a and the SiO2 film 305 b which cover the side facesof the resist pattern 304 b is also set to D, and this width D can setto 30 nm.

By performing the etching step, the oxide film is etched to remain asside wall parts on the side faces of the line part of the resist patternafter the slimming process is performed. The etching step is a processwhich etches the oxide film to remain as side walls on the side faces ofthe line part of the resist pattern after the slimming process isperformed.

Step S217 is the same process as step S116 in the fifth embodiment, andas illustrated in FIG. 31G, this step S217 is an etching step whichetches the oxide film so that the lamination layer which includes theSiO2 film 305 b and the Al2O3 film 305 a may remain only as side wallparts 305 c of the resist pattern 304 b (etch back).

The third pattern 306 that includes the resist pattern 304 b and thewall part 305 c is formed. If the line width of the third pattern 306 isset to LL3 and the space width is set to SS3, the line width and thespace width are set to LL3=LL1+D×2 and SS3=LL1+SS1−LL3.

Step S218 is the same process as step S117 in the fifth embodiment, andas illustrated in FIG. 31H, this step S218 includes a process whichremoves the resist pattern 304 b and forms the side wall parts 305 c,and a process which etches the organic film 303 by using the side wallparts 305 c as a mask. The second pattern 307 in which the line width isequal to D and the space width LL1 and the space width SS3 appearalternately is formed. Similar to the fifth embodiment, the space widthmay be set to SS2 that is equal to LL1 or SS3, and the line width whichis equal to D may be set to LL2 anew.

The second pattern 307 includes the wall parts 305 c and the organicfilm (coating) 303, and is equivalent to the mask pattern in the claims.

Subsequently, the thin film 302 is etched by using the second patterns307 as a mask, which is the same as that of the fifth embodiment. Thatis, step S219 is performed.

In step S219, the thin film (film to be etched) 302 is processed usingthe second patterns (mask patterns) 307, and as illustrated in FIG. 31I,the pattern 302 a including the thin film (film to be etched) 302 isformed. The organic film (coating) 303 may remain in the upper part ofthe pattern 302 a. The etching of the thin film 302 may be performedusing a gas containing a CF base gas, a CHF base gas, a CH base gas, oran oxygen gas.

In this embodiment, the film deposition process of step S215 may beperformed using the film deposition apparatus explained using FIGS. 23and 24 by the fifth embodiment. The silicon oxide film depositionprocess of step S216 may be performed using the film depositionapparatus explained using FIGS. 3 and 4 explained by the firstembodiment. Alternatively, the film deposition process of step S215 maybe performed, and the silicon oxide film deposition process of step S216continuously using the film deposition apparatus illustrated in FIGS. 3and 4. In that case, the processes from the slimming process of stepS214 to the silicon oxide film deposition process of step S216 may becontinuously performed within the same film deposition apparatus. Thesilicon oxide film can be formed while keeping the surface of the resistpattern pure, and uniformity in the surface of the semiconductorsubstrate of the configuration of fine patterns having the pitch belowthe resolution limit can be made better.

Since the processes which use the processing unit which carries outslimming process of the resist pattern are reducible, the cost of theprocess which forms a fine pattern can be reduced.

Next, as illustrated in FIG. 32 and FIG. 37, the configuration of theresist pattern after the slimming process in this embodiment does notchange before and after the film deposition process, and it is possibleto control the configuration of the resist pattern precisely. In thefollowing, the width dimensions of the resist pattern after the filmdeposition process are measured and estimated, and the evaluation resultwill be described. FIG. 32 is a photograph and a schematic diagram ofthe resist pattern after the aluminum oxide film and the silicon oxidefilm in Example 5 are formed.

In Example 5, the film deposition process which forms the aluminum oxidefilm on the resist pattern after the slimming process by supplying theAl source gas and the ozone gas alternately is performed, and thesilicon oxide film deposition process which forms the silicon oxide filmon the resist pattern by supplying the Si source gas and theoxygen-containing gas alternately is performed. The evaluation result ofExample 5 is compared with that of Comparative Example 3 described inthe fifth embodiment. The film deposition conditions of the filmdeposition process in Example 5 are illustrated below.

Example 5

(A) Film Deposition Conditions of Aluminum Oxide Film

(1) Source Gas Supplying Conditions

-   Source gas: TMA-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 39.9 Pa-   Gas mass flow: 100 sccm-   Supplying time: 5 sec    (2) Oxidizing Gas Supplying Conditions-   Oxidizing gas: ozone gas+oxygen gas-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 133 Pa-   Ozone gas flow rate: 200 g/m3-   Oxygen gas mass flow: 10.0 slm-   Supplying time: 15 sec    (3) Repetition Conditions-   Total cycle: 35 cycles    (B) Film Deposition Conditions of Silicon Oxide Film    (1) Source Gas Supplying Conditions-   Source gas: DIPAS (LTO520)-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 26.7-667 Pa-   Gas mass flow: 50-1000 sccm-   Supplying time: 1-10 sec    (2) Oxidizing Gas Supplying Conditions-   Oxidizing gas: oxygen gas-   Substrate temperature: no heating-   Internal pressure of film deposition apparatus: 66.7-227 Pa-   Gas mass flow: 5-30 slm-   Supplying time: 5-30 sec-   RF generator frequency: 13.56 MHz-   RF generator power: 50-500 W    (3) Repetition Conditions-   Total cycle: 120-130 cycles

FIG. 32 is a SEM photograph (left-hand side) and its schematic diagram(right-hand side) of the resist pattern after the aluminum oxide film inExample 5 is formed.

As illustrated in FIG. 32, D denotes the thickness of the aluminum oxidefilm, H denotes the height of the resist pattern, T denotes the topwidth of the resist pattern, M denotes the width of the resist patternat the position of a height which is equal to half of the bottom to topheight of the resist pattern, and B denotes the bottom width of theresist pattern.

Next, FIG. 37 illustrates the dimensions H, T, M, B, and the ratio T/Bof the top width to the bottom width of the resist pattern obtained inExample 5 and Comparative Example 2. As illustrated in FIG. 37, D1, D2and D of Example 5 are 5 nm, 25 nm and 30 nm, and D of ComparativeExample 2 is 30 nm.

As illustrated in FIG. 37, the height H, the top width T and the bottomwidth B of the resist pattern when the lamination layer of the aluminumoxide film and the silicon oxide film is formed are larger than in thecase where only the silicon oxide film is formed. That is, the decrementof the dimensions of the resist pattern before and after the laminationlayer of the aluminum oxide film and the silicon oxide film is formed issmaller than the decrement of the dimensions of the resist patternbefore and after the silicon oxide film is formed.

Next, as illustrated in FIG. 33 and FIG. 38, it is possible to preventthe resist pattern after the slimming process in this embodiment frombeing damaged. In Examples 6 and 7, the photoresist film is formed, andthe thickness of the photoresist film after the oxide film is formed ismeasured without processing the configuration of the photoresist filmand the measured thickness is estimated. The evaluation results ofExamples 6 and 7 are compared with that of Comparative Example 3.

FIG. 33 is a cross-sectional view illustrating the configuration of thefilms for measuring the amount of ashing of the resists in Examples 6and 7 and Comparative Example 3.

In Example 3, as illustrated in FIG. 33, the photoresist film 304 whichis about 300 nm thick is formed on the semiconductor substrate 301, andthe thickness of the photoresist film 304 is measured. HP1 denotes thethickness of the photoresist film 304.

Next, the film deposition process which forms the Al2O3 film 305 a onthe photoresist film 304 by supplying the Al source gas and the ozonegas alternately is performed. At this time, the supplying cycle at whichthe Al source gas and the ozone gas are supplied is changed, and thethickness HA1 of the Al2O3 film 305 a is changed to 5 nm, 10 nm, 15 nmand 20 nm.

Next, the film deposition process is performed which forms the SiO2 film305 b on the Al2O3 film 305 a by supplying the Si source gas and theoxygen-containing gas alternately is performed. At this time, thesupplying cycle at which the Si source gas and the oxygen-containing gasare supplied alternately is changed, and the thickness HS1 of the SiO2film 305 b is equal to 5 nm.

Next, the fluoric acid (HF) washing is performed, the SiO2 film 305 band the Al2O3 film 305 a are removed, and the thickness of thephotoresist film 304 is measured. HP2 denotes the thickness of thephotoresist film 304.

The amount of ashing calculated from the amount of decrement of theresist thickness is set to a difference HP1-HP2 between HP1 and HP2. Itis assumed that (1) the source-gas supplying conditions and (2) theoxidizing-gas supplying conditions for the aluminum oxide film ofExample 6 are the same as those of Example 2, and (3) the repetitionconditions are set to 35 to 140 cycles. It is assumed that (1) thesource-gas supplying conditions and (2) the oxidizing-gas supplyingconditions for the silicon oxide film of Example 6 are the same as thoseof Comparative Example 2, and (3) the repetition conditions are set to23 cycles or less.

In Example 7, instead of the ozone gas in the film deposition process ofthe aluminum oxide film of Example 6, the steam oxidation raw gas isused. In Example 7, the thickness of the photoresist film 304 ismeasured for only the case in which the thickness HA1 of the Al2O3 film305 a is set to 10 nm.

Next, the thickness dimensions and the amount of ashing HP1-HP2 of theAl2O3 film obtained in Example 6, Example 7, and Comparative Example 3are illustrated in FIG. 38.

As illustrated in FIG. 38, when the aluminum oxide film and the siliconoxide film are formed and the ozone gas and the steam oxidation raw gasare used, the amount of ashing HP1-HP2 can be reduced. That is, theamount of ashing does not increase with the increase of the filmdeposition time and film deposition thickness of the aluminum oxidefilm. Therefore, ashing of the resist is not performed by the filmdeposition of the aluminum oxide film. It appears that when the aluminumoxide film is formed, the oxygen plasma does not arise. In addition,when the aluminum oxide film and the silicon oxide film are formed, theamount of ashing is smaller than the case where the silicon oxide filmis formed. Therefore, when forming the silicon oxide on the resist, theblock performance against the oxygen plasma can be improved and thereduction of the thickness of the silicon oxide due to the ashing of theresist by the oxygen plasma can be prevented. It is easy to make thedeposition rate which forms the silicon oxide film larger than thedeposition rate which forms the aluminum oxide film. Therefore, when thealuminum oxide film and the silicon oxide film are formed, throughputcan be improved compared to the case where only the aluminum oxide filmis formed independently.

As mentioned above, in this embodiment, rather than the fifth embodimentthat forms independently the first embodiment and aluminum oxide thatform silicon oxide independently, while the configuration of a resistpattern is precisely controllable, the effect is that throughput can beraised. In this embodiment, since a resist pattern is protected whenforming the oxide film, the configuration of the resist pattern is easyto be maintained. As illustrated in FIGS. 23 and 24, when performing aslimming process within a process chamber different from the filmdeposition apparatus which performs a film deposition process, theconfiguration of the resist pattern can be controlled precisely. Themethod of using the lamination layer of the aluminum oxide film and thesilicon oxide film in this embodiment is applicable also to the LLEprocess in the third embodiment and the sixth embodiment.

In the embodiments of the invention, when forming mask patterns (or finepatterns) from the silicon oxide film formed on the pattern organicfilm, the cost of the process or apparatus for performing the slimmingprocess of the resist patterns can be reduced, and the cost of theentire mask pattern (or fine pattern) forming process can be reduced.Moreover, it is possible for the embodiments of the invention to performthe slimming process or the film deposition process while ensuring thatthe difference between the top width and the bottom width of each of theresist patterns is made small, and it is possible to form mask patterns(or fine patterns) with a good configuration.

The present invention is not limited to the above-described embodiments,and variations and modifications may be made without departing from thescope of the invention.

What is claimed is:
 1. A mask pattern forming method comprising:providing a substrate including a first pattern on a thin film; slimmingthe first pattern on the thin film into a second pattern; forming afirst conformal film on the second pattern and the thin film; andforming a second conformal film on the first conformal film, wherein thefirst conformal film and the second conformal film constitute the maskpattern, wherein slimming the first pattern and forming the secondconformal film are performed using an oxygen containing gas plasma andforming the first conformal film is performed without using any oxygencontaining gas plasma, and wherein slimming the first pattern andforming the first conformal film and the second conformal film areperformed consecutively in a same film deposition apparatus.
 2. The maskpattern forming method according to claim 1, wherein slimming the firstpattern and forming the first conformal film and the second conformalfilm are performed in a same process chamber.
 3. The mask patternforming method according to claim 1, wherein slimming the first patternand forming the first conformal film and the second conformal film amperformed at temperatures below a heat-resisting temperature of thepattern.
 4. The mask pattern forming method according to claim 1,wherein slimming the first pattern and forming the first conformal filmand the second conformal film are performed at temperatures below 100degrees C.
 5. The mask pattern forming method according to claim 2,further comprising: purging the process chamber between the slimming thefirst pattern and the forming the first conformal film.
 6. The maskpattern forming method according claim 1, wherein the first conformalfilm comprises metal oxide and the second conformal film comprisessilicon oxide.
 7. The mask pattern forming method according to claim 1,wherein forming the first conformal film is performed by a cycle ofadsorbing an organic metal based precursor on the pattern and the thinfilm and oxidizing the organic meta 1-based precursor.
 8. The maskpattern forming method according to claim 1, wherein forming the secondconformal film is performed by a cycle of adsorbing an aminosilane-basedprecursor on the first conformal film and oxidizing theaminosilane-based precursor.
 9. The mask pattern forming methodaccording to claim 1, further comprising: etching the first conformalfilm and the second conformal film so that the first conformal film andthe second conformal film remains as a side wall part on a side face ofthe pattern.
 10. The mask pattern forming method according to claim 9,further comprising: removing the pattern so that the side wall part ofthe first conformal film and the second conformal film remains on thethin film.